Penny

Penny is the show's first and main female protagonist. She lives in apartment 4B across the hall from Leonard Hofstadter and Sheldon Cooper, who live in apartment 4A. Her full first name is possibly "Penelope" as implied by "The Barbarian Sublimation", and her surname has not yet been revealed, but due to her recent engagement to Leonard, she might change it to Hofstadter when they get married. For a while her last name was Johnson while unknowingly married to ex-boyfriend Zack Johnson.

An aspiring, but mostly unsuccessful actress, she was born on a farm near, Nebraska, and worked at The Cheesecake Factory as a waitress until she quit in "The Occupation Recalibration" (S7E13) to take up acting full time. Penny was the original female lead in the show before being joined by Bernadette Rostenkowski and Amy Farrah Fowler.

She has been Leonard's love interest for most of the show, with the two dating briefly in the first episode of the second season, for most of the third season, and they rekindled their romance in "The Recombination Hypothesis". As of "The Gorilla Dissolution", she and Leonard are engaged.

Even though she is considered part of the guys' group, she represents the "dumb blonde" for viewer context in the series with a lot of street smarts and communication skills to compensate for her lack of academic knowledge.

Origin and Development
Originally, two different female leads were written for the Pilot episode. The unaired pilot episode had an alternate version of the female lead named Katie. Katie was bitter and received by audiences to be too mean to Sheldon and Leonard. Kaley Cuoco did not portray this alternate version of the female lead, but instead was hired to do the second version filmed after the unaired pilot, which was sociable and nice and was the one that the producers decided was the more interesting and appealing out of the two.

Some of Penny's comedic role in the series is rooted in her ability to execute practical and simple solutions to problems of which the guys try to solve through complicated or scientific means. For example, in the episode "The Pants Alternative", Sheldon reveals that in spite of his ability to talk excessively to people in small groups, he has a severe case of stage fright, and wouldn't be able to accept an award. While Leonard tries to get to the root of his problem through a psych evaluation, and Raj attempts to use meditation, Penny solves the problem by having him buy a new suit and getting him intoxicated right before he makes his speech.

As the series developed, Penny's character took on the theme of being the virtual polar opposite of Sheldon, which created a unique relationship between the two characters. Penny's relationship with the other guys is usually perceived as something of an older sister, or a mother in some cases with Sheldon. She has also had a romantic, on-and-off relationship with Leonard.

Background
When she first met the guys in the Pilot, Penny was writing a screenplay about a girl from  who travels to Los Angeles at the age of 18 to become an actress, but ends up working at The Cheesecake Factory instead. When Leonard asks if the screenplay was autobiographical, she replies that it isn't, because she is from a small town outside of Omaha, Nebraska.

Penny moved into the apartment building because she split with Kurt, her boyfriend for 4 years. She says she still loved him, and insinuates he cheated on her. The shower in her apartment was broken at the time, so the boys offered her theirs. Her apartment is sloppy and disorganized, but Penny appears to like it that way.



She is either oblivious to or completely aware of her effect on the boys, because within minutes of meeting him, she asked Leonard to retrieve her television set from Kurt's apartment, which he immediately set out to do. Penny is aware of Leonard's crush on her, and it is hinted throughout the series that some of the feelings are reciprocated. At the end of season one, Penny goes on a date with Leonard. Leonard is nervous, and Penny slightly withdrawn, but they nonetheless share a kiss.

In season two, there was some initial enthusiasm between Penny and Leonard. However, they later develop insecurities concerning their relationship. Penny was worried that she was not smart enough for Leonard, and lied about graduating from community college because she thought it would make Leonard respect her. The relationship quickly deteriorated and she goes back to dating different guys. Leonard showed Penny some literature on Pasadena City College and she interpreted it as him wanting a woman with more education and they break up.



She gives relationship advice to Sheldon and Leonard fairly often: Leonard, when he has problems with Priya or Stephanie, and Sheldon when he's with Amy. She also starts to become geekier through the guys. She makes inadvertent references to Star Trek, and, thanks to Sheldon, becomes addicted to Age of Conan. She also dates Stuart, who runs the comic book store. However, when Penny and Stuart are making out, she accidentally calls him Leonard, and as a result, they stop seeing each other.



When she learns that the guys are going on an Arctic expedition, she is visibly upset, buys Leonard a farewell gift, and tells herself, after speaking with him, that she wishes he wasn't going.

In season three, when the boys get back from the expedition, Penny kisses Leonard the second she sees him; however, Leonard and Penny's relationship has a rocky start because they have some trouble getting used to being more than friends, but they eventually start a relatively stable relationship.

Family


Penny's sister is mentioned as having shot her husband while they were both intoxicated.

It is known that she has a nephew who turned 13 in season two, likely the son of Penny's sister.

When Christy (Penny's friend from Omaha) comes into town, Penny reveals that she has a brother and at least one male cousin, as she claims that Christy slept with the former while being engaged to the latter.

Her brother also works in a meth lab, though it's not clear if it is the same brother Christy slept with. This fact is first hinted at in "The Pirate Solution" as Penny describes him as 'kind of a chemist' and tells Leonard that he would like him. It is finally confirmed in "The Rhinitis Revelation" when she asks God to make her brother stop cooking meth, but without involving the authorities. In season 7 in "The Hesitation Ramification", Penny mentions that her Dad gathered all the relatives together to see her scene on NCIS, which included getting her brother a day out of rehab. They also bought a large sandwich to share. When her scene is cut, Penny mentions that the sandwich and her brother are gone and as far as she knows her brother is on the way to Mexico.

Sheldon implies Penny's mother is overweight and in "The Flaming Spittoon Acquisition" says that her mother must have used cannabis when she was expectant with her.

In season two, "The Maternal Capacitance", as Penny is explaining to Beverly that her father stopped playing catch with her when she developed breasts, she quotes her mother talking to her father, and suggests his name is Bob, though it is later revealed in "The Boyfriend Complexity" to be Wyatt.

Family Members

 * Father: Wyatt
 * Mother: Unnamed
 * Brother: Unnamed
 * Sister: Unnamed
 * Nephew: Unnamed
 * Cousin: Unnamed

Work Experience
Penny is described by others and considers herself a waitress/actress though she has told Leonard that she is a "professional" actress despite her short acting resume. Her income is derived from working at the Pasadena Cheesecake Factory as a waitress and living off the guys in Apartment 4A. In "The Occupation Recalibration" (S7E13) she quits the job as a waitress and declares she would engage herself in acting area full-time. Leonard has never discouraged Penny when she joins them for takeout meals, piggybacks on their Wi-Fi connection and paying for her movie tickets and other bills.

As of S7E19, her acting career credits consists of


 * A topless role in a low budget horror film Serial Apist. This movie happened before she moves into Apartment 4B (in the Pilot), but is not revealed to the audience until "The Hofstadter Insufficiency" (S7E01).
 * A one night showcase production of the musical Rent ("The Loobenfeld Decay", S1E10).
 * A production of The Diary of Anne Frank, performed over a bowling alley; ("The Terminator Decoupling", S2E17; later mentioned in "The Psychic Vortex", S3E12 and "The Recombination Hypothesis", S5E13).
 * A hemorrhoid commercial ("The Skank Reflex Analysis", S5E01; later mentioned in "The Recombination Hypothesis", S5E13; in "The Transporter Malfunction", S5E20, she says she gets a residual check from her commercial, which presumably still refers to this one).
 * Acting class production of A Streetcar Named Desire ("The Monster Isolation", S6E17).
 * A bit part in NCIS that was cut from the final show ("The Hesitation Ramification", S7E12).
 * Playing an ape/human clone in Serial Apist 2, Monkey See, Monkey Kill ("The Indecision Amalgamation", S7E19) Fired in "The Gorilla Dissolution" after she wanted to improve her performance.

According to the production staff, Penny will at least for awhile, be a pharmaceutical representative, salesperson, at Bernadette's company and will ditch acting for at least awhile.

Leonard
Leonard almost immediately falls for the girl who moved across the hall from him and his roommate in the pilot episode, and has spent much of the entire series trying to win Penny despite the doubts expressed by many of his peers. Penny shows no affection for Leonard until "The Hamburger Postulate", when she hears of his failed attempt at a relationship with Leslie Winkle, though the sign is seen only by the audience. Despite these signs she continues to date other men, though she regularly visits Leonard's apartment everyday to see him.

She and Leonard went on their first date in the finale of the first season, but they were unable to start a relationship because Penny feared he would get bored with her due to his high intelligence compared to her own. Regardless, Leonard continues his pursuit of Penny throughout the second season, even going as far as confronting her towering ex-boyfriend, Kurt in an effort to retrieve the money he owes her.

After Leonard returns from his three-month research trip at the North Pole, Penny immediately kisses him, having missed him greatly. Leonard happily returns her affections and they later make love for the first time.



Despite another rocky start, Penny remains happy with Leonard throughout most of season 3, forming the kind of stable relationship that she hadn't seen in over two years.

Things went downhill, however, when Leonard told Penny "I love you," and became angry and insecure at her unwillingness to reciprocate. The pressure he places on Penny--along with a heated argument that occurred between the two during a bowling match--eventually caused her to abruptly end their relationship, leaving Leonard heartbroken.

They later agree to stay friends, even though it's clear that Penny has never stopped liking Leonard, and as she revealed in a game of truth or dare with Amy and Bernadette, only broke up with him because she became scared after Leonard told her he loved her. When the girls point out that she could lose Leonard to another woman as a result of her decision, Penny storms into her bedroom and slams the door.

Though Penny keeps an emotional distance between herself and Leonard throughout the fourth season, her feelings for him are hinted at on more than one occasion. Once was during a New Year's Eve party at the comic book store, when Penny stares uncomfortably at Leonard while she kisses her date, Zack Johnson. Earlier that evening, Penny let it slip out to Leonard that he was one of the reasons why she had been feeling sad recently.

Their friendship eventually becomes strained when Leonard begins dating Raj's sister Priya, causing confusion for Penny as she starts to reconsider her feelings for him. The situation gets worse when Penny and Priya grow jealous of each other, forcing Leonard to cut his ties with Penny permanently. During their time apart, Penny becomes very close with Amy and Bernadette, who provide comforting support and help her understand the depth of her emotions regarding Leonard's new relationship.

In the season finale, Penny admits to Raj that she "screwed up," and that she never should have broken up with Leonard. Coincidentally, Leonard told Raj how he ached for Penny the same way a year earlier.

Penny again reveals her regret in season 5 to Sheldon (without mentioning Leonard directly), telling him that he should never take his relationship for granted. The result was Sheldon thinking that she had a thing for him.

Penny finally makes her move after Leonard and Priya break up later in the season, asking Leonard out to the movies, but hiding her feelings by keeping things casual and telling him that sex was off the table. Leonard misses the hint however, and the night turns into a disaster when the two attempt to make each other jealous by flirting with other people they encounter during the date. They do make up in the end, and Leonard's hopeless infatuation for Penny surfaces when he becomes submissive once more in an attempt to sleep with her.

At the spur of the moment in "The Recombination Hypothesis", Leonard asks Penny out on a date after he imagined what getting back with her might be like. He also realizes he over analyzes everything too much. Their real date ends successfully and they agree to take their relationship slow in "The Beta Test Initiation".

In "The Launch Acceleration", Penny suggested that they move up their relationship. However, Leonard ruins the mood when he asks her to marry him during intimacy. They later meet and Penny, unlike their first split, managed to reject his proposal and still stay in a relationship with him. During "The Countdown Reflection," they watch Howard's space launch while holding hands to comfort each other.

Things remain awkward between them in the months following the failed marriage proposal. Raj, who was butting into one of their dates, insisted that Penny tell Leonard that she loves him, but she was not ready and threw him out of the apartment.

Penny later expresses more doubts about whether she truly loves Leonard to her friends in "The Decoupling Fluctuation," describing her passion for him as "boring" compared to her previous relationships. She nearly breaks up with him at the conclusion of the episode, but changes her mind at the last moment and ends up sleeping with him to hide the truth. The next day Leonard again expresses his unparalleled love for Penny via text message,  making her feel even guiltier as she struggles with whether or not she wants to be with him.

Their relationship takes a completely different turn however, when Penny visits Leonard's workplace with Amy and sees Sheldon's attractive assistant Alex flirting with him in the cafeteria, causing Penny to become jealous and confused about her feelings for Leonard once again.

Her feelings continue to grow in "The Holographic Excitation," when Penny decides to drop by Leonard's laboratory after Amy and Bernadette urge her to take a more active interest in his work. Despite her lack of knowledge in science, Penny becomes fascinated as Leonard uses holographic imaging to explain the basis of string theory and the holographic principle, speaking in a way that sparks her passion and earns him the kind of affection (bordering on love) that he had last seen during their first night together after he returned from the North Pole.

In "The 43 Peculiarity", Penny is working with an English fellow student named Cole on an oral class project. Leonard is jealous so he follows him down the apartment stairs and tells him to watch out for "Penny's boyfriend" since he is a gang member. Penny is upset with Leonard and the two later meet in the hallway and have an argument. Penny tells him that she cannot believe that he does not trust her and that he embarrassed her in front of Cole who knew who he was since his picture is on her refrigerator. Penny continues to tell him that he is the one she is with and unwittingly mentions that he knows that she loves him. Leonard is stunned and tells her that that is the first time she ever said that she loves him. He then interprets her stunned reaction and asks if they aren't going to make a big deal about her confession. She agrees and runs off to cry.



In "The Egg Salad Equivalency", after Alex asks Leonard out to dinner and didn't tell Penny about it, she begins to feel really insecure about their relationship. Leonard apologizes by playing her an apologetic song on his and reassuring her that nothing will ever happen between him and Alex. She decides instead of feeling bad, she will do something about it. First, she looks into science classes at college, but they sound boring. Then she buys some geek glasses to look smart, which does affect Leonard as he pulls her into his bedroom.



In "The Bakersfield Expedition", she develops an interest in comic books and Thor's hammer.

In "The Spoiler Alert Segmentation", Leonard suggests that he move in with Penny after he again gets exasperated with Sheldon. He asks her if she's all right with it, but she only agrees not to hurt his feelings and even tells Sheldon. When Amy confronts Penny since she can't move in with Sheldon, Leonard over hears. Penny tells him that he never asked her if she was ready and Leonard ends up back in apartment 4A.

In "The Tangible Affection Proof", Leonard takes Penny out to dinner for Valentine's Day. Penny feels that all the effort never meets the expectations. Penny sees a former boyfriend proposing to the girl that broke them up. Leonard again tries to propose and Penny stops him. That night Leonard tells Penny that she made a mess of the whole evening. Penny finally admits that she has commitment issues and the obvious path of their relationship ending in marriage scares her. Leonard then puts the responsibility of proposing on her and she should do it when she's ready. In the end, she does ask him to be her Valentine, to which he accepts.

In "The Closure Alternative", Penny was concerned about the passion Leonard showed for science, comics and various television shows while she had no passion in her life. Her dreams had always been to become a famous movie star and live a glamorous life. Anything less than that she felt was settling. Her epiphany comes that she is passionate about her boyfriend Leonard and all her wonderful friends.

In "The Bon Voyage Reaction", Leonard takes a job working on a Stephen Hawking expedition in the North Sea for four months over the summer. Penny will miss him, but knows that it is a good opportunity and sends him off. At the airport, she is fussing over him like his wife sending him off on a business trip. She also has to watch Sheldon over the summer, too.

In "The Hofstadter Insufficiency", Leonard hurts Penny because he seems to be having such a great time on the ship; she thinks that he is not even missing her. In "The Deception Verification", Leonard makes up for it by showing up early and hides in her apartment so that they can spend time together a couple before telling the gang that he's back. It works until Amy and Sheldon find them together after they think that Penny is cheating on Leonard.

In "The Raiders Minimization", Penny purchases a psychology book that Beverly Hofstadter has written about all his problems growing up called The Disappointing Child. Leonard is extremely embarrassed, so Penny does whatever he wants to make him feel better, including having sex in his lab. He mentions her actions to Howard, so Bernadette tells Penny. She dresses up for sex to tempt him, and then for revenge makes him Skype with his mother to discuss him using his mother's past with him to manipulate elements of his sex life.

In "The Occupation Recalibration" (S7E13), Penny is frustrated that she has nothing to show for herself after ten years in LA. Leonard points out that she does have him. A tipsy Penny then gets down on one knee and proposes. Leonard hesitates to answer her and she storms out. Leonard is worried that Penny is now going to break up with him. In the next episode, Penny tells Leonard that he did the right thing since she was a mess that night and they stay together.

In "The Table Polarization", the gang wants to add a dining room table to Apartment 4A which Sheldon objects to. Penny gets Leonard to pick out a dining set that she likes and gets Leonard to stand up more against Sheldon. Sheldon objects to Penny changing Leonard to stand up against him. Penny points out that Amy has changed Sheldon who agrees and then decides to break up with Amy.

In "The Mommy Observation", Penny seems to feel that if she were a successful actress and had to move around, Leonard would leave his job even if it was a tenured position to follow her since she would be making more money.

In "The Proton Transmogrification" Penny asks Leonard to marry her to get their marriage proposal rejection score from 2 to 1 to even. She also gets upset when she keeps getting all the Star Wars in-jokes during their Star Wars' Day celebration.

In "The Gorilla Dissolution" Leonard and Penny are back in her apartment after a long tiring day. Penny wants to start making smarter decisions about her life. She says that they could get married. Leonard asks her if he is a smart decision, like choosing a healthy boring bran muffin. Penny doesn't care what pastry he is because she is CHOOSING HIM. Leonard is still talking about being a pastry like a strawberry Pop Tart that she is excited about. Penny tells him to forget about it. Leonard does want to marry her, but feels that she is just feeling sorry for herself because she was fired. Penny explains that it may seem that way, but getting fired made her think that fame and fortune is not what is going make her happy. Leonard wants to know what she needs. "You, you stupid strawberry Pop Tart!" Leonard finally says that he guesses that he is in, which also bothers Penny. Leonard then retorts that it is an excited "I guess I'm in" and they agree that they are engaged which seems somewhat anti-climatic. To change the mood, Leonard pulls a ring out of his wallet that he has had for a couple of years, gets down on one knee and asks Penny formally. Penny says "yes" and he slips the ring on her finger that still has ape hair glued to it and they embrace.

In "The Status Quo Combustion", Leonard and Penny announce their engagement; however, the gang is more excited about Raj and Emily hooking up. Leonard goes searching for the missing Sheldon and finds him at the railroad station leaving time to think about all the changes in his life. Leonard wants him to come home, but Penny convinces him that he should let him go.

Sheldon
Penny and Sheldon constantly argue with each other. Sheldon is quick to take shots at Penny's intelligence, waitressing job, and failing acting career (though he generally doesn't understand that these statements are detrimental) while Penny throws off his personal routines, such as during "The Panty Piñata Polarization" when Penny messes up Sheldon's laundry night. Despite their differences, Sheldon and Penny are very close, and are quick to help each other. They have taken care of each other on multiple occasions; often times doing things they really don't want to do to make each other feel better. Penny has stated that they are friends.

Major examples are when Penny takes care of Sheldon when he is sick, and when she lets him stay at her apartment when he gets locked out, even letting him sleep in her own bed. Sheldon was also quick to come to Penny's aid when she called for help after falling in the shower and dislocating her shoulder, going so far as to drive her to the hospital, despite not knowing how to drive.

Many of these occurrences end with Penny singing Soft Kitty to Sheldon to make him feel better or when he is sick; Sheldon sang it to her on one occasion as well. One of the biggest examples of their friendship is that despite his own rule of avoiding physical contact with people, Penny was the first person Sheldon hugged on the show.

And remains one of only three people he's hugged who aren't members of his family, the only others being Wil Wheaton and Amy Farrah Fowler. To date, Sheldon and Penny have hugged two times: once in "The Bath Item Gift Hypothesis" and again in "The Large Hadron Collision". Sheldon also is in the habit of insulting Penny when he asks her for a favor.

In "The Werewolf Transformation", Penny convinces him to let her cut his hair since his barber is in a coma. She listed times she's taken care of him, saying that she's taken him to Disneyland, kicked a bully in the nuts for him, sings him Soft Kitty when he's sick, and that he's even seen her naked once. Sheldon eventually agrees to let Penny cut his hair.

In "The Closure Alternative", Penny decides that she is passionate about her friends and tells Sheldon that she is glad he is in her life.

In "The Bon Voyage Reaction", Leonard asked Penny to keep an eye on Sheldon while he's gone. They hung out together and Penny took him shopping, developing a brother/sister relationship. In "The Hofstadter Insufficiency", they didn't even get on each other's nerves, and Penny played the games that Sheldon wanted to play or usually played with Leonard. Sheldon even tried to comfort a lonely Penny and let her hug him with very little objections. After Sheldon had a nightmare, he knocked on Penny's door early in the morning. He woke Penny up and all she did was ask what he wanted, she was neither mad or disgusted by his intrusion, indicating a good, stable, friendly relationship.

In "The Romance Resonance", Howard makes a romantic gesture to Bernadette by writing her a song. Leonard mentions that Penny never does anything like that, except for sex which doesn't count. Penny is determined to romance Leonard. Raj can only suggest that she cook for him or reenact a scene from a romantic movie. Finally after a candlelight dinner, Penny puts on some romantic music, spreads rose petals into her neatly cleaned bedroom and presents Leonard with a first edition of his favorite book from when he was growing up, The Hitchhiker's Guide to the Galaxy. Unfortunately, Leonard had already purchased it after he had seen it in a secondhand bookstore with her. Penny gets upset telling him about all the thoughtful things he had done for her and shows him her collection. An airplane, a rose given to her "just because" and the eleven-page letter he wrote her after the first time they slept together. Leonard was very touched that she kept all these things. He then kisses her, showing that Penny did do something romantic.

In "The Thanksgiving Decoupling", Penny reminisces about a Thanksgiving she had in Las Vegas with former boyfriend Zack Johnson which included one of those silly fake weddings. Penny appears devastated when her friends inform her that the wedding was real and she is married. Penny and Leonard argue about how quickly she should get her annulment so Penny invites Zack over to their Thanksgiving dinner at Howard's mother. Zack appears as dimwitted as ever telling them that breaking up can be hard on the kids which they don't have. Finally, Penny and Leonard make up and she tells him that the next time she gets married it will be for real, for love and (jokingly) or for money.

In "The Cooper Extraction", Amy points out to the gang that most of them would not know each other if Sheldon had not been part of their lives. Penny feels that Leonard would never have successfully asked her out at the Cheesecake Factory, while Leonard suggests that she would have ended up with Zack. In the Zack story, he spent all the rent money on some magic beans. Amy thinks that if Amy and Leonard were out of the picture, the lusty Penny would try and seduce her neighbor Sheldon much to Penny's disgust and the guys' amusement.

In "The Anything Can Happen Thursday Recurrence", Penny takes Sheldon to a psychic at a time when he can't decide what new problem of science to follow after string theory is disproven. The psychic knows that he has trouble with his girl and that following that relationship will give him the answers he seeks.

Howard
Upon meeting, Howard constantly made passes at Penny in ways that made her deem him "disgusting". One point she calls Howard "pathetic and creepy" which breaks his spirit in "The Killer Robot Instability". Leonard makes Penny go and apologize, however she ends up breaking Howard's nose when he tries to kiss her. Their dynamic remains the same for the most part throughout the series, but begins to change when Howard begins to date Penny's friend Bernadette. Although Penny is not a fan of him, she admitted that she considered Howard a friend in 'The Engagement Reaction", although they rarely hang out outside the group. Howard flirts with Penny much less and becomes more casual towards her after he begins his relationship with Bernadette, which Penny obviously enjoys, although she still pokes fun at him.

Raj
Like with all other women except his mother and sister (and thus one would assume all female relatives), Raj is unable to speak to Penny unless he is intoxicated or on medication. They hang out within the group a lot and Penny occasionally attempts to tease him into talking to her. After she goes to a People magazine reception with him, he introduces her to his parents as his girlfriend, though they want him to find an Indian lady. Raj begins to like Penny as the series goes on and the two end up getting inebriated and appear to have had intercourse. Once he can speak to her sober, they become each other's confidants.

Later, Raj tells Penny that nothing physical happened between them as she straightaway asked if he had protection and then he had trouble putting it on and she tried to help so he ejaculated prematurely. Raj asks Penny not to tell anyone and Penny promises to keep silent. Raj attempts to actually date her, but she tells him she just wants to be friends. Despite their rough past, Penny attempts to find a girlfriend for Raj and comforts him when he needs it. She also invites him along to their ladies' night out while the guys play their Dungeons and Dragons Christmas game. He discovered he had come over his Selective Mutism when he was able to talk to Penny about his breakup with Lucy without being under the influence in "The Bon Voyage Reaction".

Bernadette
Penny and Bernadette worked together at The Cheesecake Factory until Bernadette received her PhD and became a microbiologist. However, they remain close friends. Penny introduced her to Howard on a blind date. She is the first person outside of the few boyfriends that Penny is seen to socialize with on a regular basis. They enjoy spending time at Penny's apartment, comforting each other, and going out together.

They also hang out with the guys together once Howard starts dating Bernadette. In "The Countdown Reflection", because Bernadette wants to get married to Howard before he goes into space, Penny, along with Amy, Sheldon, Leonard and Raj become ordained as ministers to so they can officiate at the wedding ceremony.

Penny is notably upset when she is in the middle of Bernadette and Amy's fight during "The Parking Spot Escalation". She is really hurt once Amy takes a swing at Bernadette with her purse hitting Penny in the face and breaking her nose.

Amy
When Bernadette and Penny were having a ladies' night, Amy injected herself into Penny's life by getting herself invited. In no time, she claims that she and Penny are best friends and calls her "bestie". When she initially hangs out with Penny and Bernadette, her lack of social skills make it somewhat awkward, but as she spends more time with them they bond and the three become their own group as a counterpart to the group of guys.

The two gradually form a tight friendship and continue to spend more time together and are quick to aid one another whenever the other needs it. Amy is aware that Penny is the planet that her social life revolves around and quickly reverses her course if she is mad at her or is annoying her. Amy gave Penny a large unflattering painting of the two of them to celebrate their friendship, which at one point the former realizes the latter hates. Penny rushes over to Amy's apartment to rescue their friendship and re-hangs the painting in her apartment on the fourth wall (facing the audience).

In "The Shiny Trinket Maneuver", when Amy had her argument with Sheldon, Penny took Sheldon to the jewelry store to buy a gift. Sheldon ends up getting Amy a tiara. Penny is more than happy putting the tiara on Amy, which makes Amy ecstatic. In "The Weekend Vortex", Amy confides in Penny when she had an awful time at her aunt's birthday party because Sheldon backed out on his promise to attend an MMORPG marathon. Penny gets them to play quarters where the loser will need to drink beer. Amy turns out to be very good at the game from all the time she spent as a child throwing coins wishing for friends, and as a result, Penny gets intoxicated. She convinces Amy to make a scene and the two barge into the guys' apartment as they are in the middle of their marathon. Amy fails to keep up her ruse of leaving Sheldon for a make-believe character named Arman, and Penny comes to her rescue by telling Sheldon the truth. Penny is also very upset to be in the middle of the argument between Amy and Bernadette over



Howard's parking space in "The Parking Lot Escalation", especially after Amy accidentally hit her in the face with her change-filled purse, giving Penny two black eyes and a broken nose.

In "The Cooper/Kripke Inversion" Penny asks Sheldon if he is ever going to sleep with Amy. After Sheldon says that it is a possibility, Penny gets very excited for her friend. In "The Love Spell Potential", Penny tells Sheldon's and Amy's "D&D" characters to "do it" in the game, which upsets Amy and causes her to leave. In "The Spoiler Alert Segmentation" Penny ruins Amy's chance to move in with Sheldon because she is ready for Leonard to move in with Penny. Sheldon also didn't want Amy moving in either. To prove that she could do it, Amy tells everybody that she should move in with Penny which Penny also disapproves of.

Priya
Priya was envious of Penny because of Leonard's previous relationship with her, and eventually asked him to stop communicating with Penny. Though Penny did so, she became angry towards Priya for dating Leonard, as she had only recently realized she still had feelings for him. The friendship is restored when Priya becomes friendly with Penny in the engagement reaction episode where they strike up a friendly conversation and bond in the process, although Penny remains silently jealous. When Priya's relationship with Leonard ended after admitting that she slept with her former boyfriend a few weeks ago, Penny and Leonard start dating again.

Stephanie
Penny wanders into Leonard's apartment begging to have a cup of coffee. Dr. Stephanie Barnett asks Leonard who this woman is who comes into his apartment in the morning in her underwear. Both Penny and Sheldon make it difficult for Leonard to explain Penny whom he describes as one of many neighbors who wander the apartment building which has no dress code. Leonard exclaims that he has never slept with Penny. Sheldon adds that it wasn't from a lack of trying. Sheldon also describes Stephanie as a valuable roommate which Leonard denies that they are living together. Penny goes to check out Leonard's bedroom and finds enough of Stepanie's stuff that Leonard realizes that they are living together.

Quotes
"Hi (Hi, Hi) (Hi, Hi)...Hi?" [Meeting Sheldon and Leonard for the first time]

"Amy's right...I do want to fling my poo at her." [To herself after seeing Priya]

"Sheldon, you forgot something...this plasma grenade. (explosion) Look, it's raining you!¨ [Teasing Sheldon after beating him in Halo]

"Okay, sweetie...I know you think you're explaining yourself, but you're really not." [To Sheldon when she can't understand Sheldon]

"Who's Radiohead?" [Challenging Sheldon at his knowledge]

"Not since I found out that the teddy bear you gave me had a webcam in it." [To Howard when he tricks her at the door]

"When I go, I usually just get hammered and ride the cable cars." [Talking about San Francisco]

"Come on, Sheldon, you can't leave. Don't you need to stay here so the mother-ship can find you when it returns?" [To Sheldon when he tries to relocate.]

"Okay, Leonard, I know I said I could handle your roommate, but I was wrong, we're going to have to break up." [To Leonard when Sheldon wakes them up at night]

"Just move your scooter before I pick it up and throw it in the dumpster!" [To Howard after he makes a dirty joke to her]

"Soft Kitty, warm Kitty. Little ball of fur. Happy kitty, sleepy kitty. Purr, Purr, Purr." [To Sheldon whenever he's sick]

"She agreed to go out with for free, what more do you want?" [To Howard about Bernadette]

"Sheldon tried to take the ring and I punched him." [After giving Sheldon a whopper in the nose]

"Bark once if you want me to call PETA." [to Cinnamon]

"They're gonna get beat up at Walgreen's." [About Howard and Raj going Goth]

"Do or do not, there is no try." [Quoting Yoda after intercourse]

"It's just rum. It stopped being eggnog about a half hour ago" [To Leonard at Christmas]

"Actually, that's not true, Leonard. Recently I've been thinking that given the parameters of your experiment, the transport of electrons through the aperture of the Nano fabric metal rings is qualitatively no different from the experiment already conducted in the Netherlands...observed phase shift in the diffusing electrons inside the metal ring already conclusively demonstrated the electron analog of the Aharonov-Bohm quantive ference effect...That's it, that's all I know. Oh, wait! Fig Newton's were named after a small town in Massachusetts not the scientist!" [Penny unknowingly insulting Leonard's work]

"Yeah, you can't sit there... oh no, you see in the winter it's close enough to the radiator so that he's warm, but not so close that he sweats. In the summer, it's directly in the path of a cross breeze created by open windows there and there. it faces the television at an angle where it isn't direct so he can still talk to everybody, but not so wide that the picture looks distorted." [Explaining to Bernadette why she can't sit in Sheldon's spot]

"What's up, buttercup?

What's the word, hummingbird?

What's the gist, Physicist?" [Greeting Sheldon at the door]

"Leonard, look. Sheldon's hugging me!" [To Leonard as she and Sheldon embrace]

"Hey, guys, what'cha doing? Going out to discover electricity?" [To the guys with their kites]

"Who do we love?!" [As Sheldon knocks on her door]

"I got my geek on, boys!" [To the guys]

"Out of coffee, need coffee." [Coming over for coffee]

"I smell Chinese food." [Using smell to find food]

"What up, Moon Pie?" [Teasing Sheldon over the phone]

"Leonard...will you be my Valentine?" [After she agrees that she will propose to Leonard]

"Your mom still here? - Come on in." [To Leonard when asking for alcohol]

"Mrs. Cooper, hey, it's Penny. Yeah, I think I broke your son." [To Mrs. Cooper after she gets Sheldon]

"Oh, this isn't alcohol. This is a magic potion that makes me like you." [To Sheldon about playing D&D]

"I drink my potion." [To everyone as they prepare to battle imaginary ogres]

"I'm happy Leonard's found someone... not that anyone asked". [To the guys about Leonard dating Priya]

"Awww, he's got the same look my little nephew gets when he can't figure out how I got his nose." [Teasing Sheldon about why he can't figure out the magic trick]

"Sweetie, I understand you have scars that non-professional can heal." [to Sheldon]

"Well then, good news! Today's the day a girl's finally going to touch you in your little special place." [Before kicking the hacker in the groin]

"Yeah, My mom gave me the same lecture about my virginity." [To Leonard about opening the toys she bought]

"All right, Howard Wolowitz, listen up! You sign anything she puts in front of you. Because you are the luckiest man alive if you let her go there is NO way you can find anyone else. Speaking on behalf of all women, it's not going to happen - we had a meeting." [To Howard about the prenup]

"Oh, a couple of virgin Cuba Libres who turned out to be a little slutty... Hey you do your experiments, I do mine." [To Leonard about tricking Sheldon into getting drunk]

"Yeah, well, your Ken can kiss my Barbie." [To Sheldon about Laundry Night]

"Sheldon, that's not what girlfriends are for. Although you don't use them for what they're for, so what do I know?" [To Sheldon about relationships]

"So that means, you're a doctor, you're a doctor, you're a doctor, you're a doctor and ... Howard you know a lot of doctors." [Teasing Howard about not having a doctorate]

"No, no, no, no, I didn't forget. Um, there's this cat in a box and until you open it, it's either dead or alive or both. Although, back in Nebraska, our cat got stuck in my brother's camp trunk, and we did not need to open it to know there was all kinds of dead cat in there." [To Sheldon about Schrodinger's cat]

"Happy Valentine's Day." [To Sheldon about getting sick]

"Apparently, the one fella tried to adjust the thermostat, then the other fella went bat-crap crazy." [Sarcastically describing Leonard and Sheldon's fight]

"You wanna turn yourself into some sort of robot?...  Okay, here's my question: Didn't you already do that?" [To Sheldon about living longer]

"Holy crap on a cracker!" [Shuddering over Sheldon and Ramona]

"Aw, honey, the buses don't go where you live, do they?" [To Sheldon about touching his onion rings]

"And what kind of doctor removes shoes from asses?" [Sarcastically threatening Sheldon about being in her apartment]

"What up, Shel-bot?" [To Sheldon's computer monitor]

Trivia

 * Penny was 21 years old at the beginning of the show, which means she is the youngest of the gang. Penny is a Sagittarius, meaning she was born between November 22 and December 21. In "The Prestidigitation Approximation", Howard does a fake magic card trick in which the sum of the digits of one's birth date, excluding the year, are used to get the number of the card to be selected. Penny turns over the fifth card, making her birthday in the span of the Sagittarius one of four possibilities: November 30th, December 2nd, December 11th, or December 20th. If Penny's birthday is November 30th (1+1+3+0=5), it would match the birthday of Kaley Cuoco (Saturday, November 30, 1985) exactly. The only possible birth date of Penny would be Monday, December 2, 1985 if one alternatively interprets the rules of Howard's card trick as requiring one to turn over the card corresponding to the sum of the digits of the month and adding the day. Though David Underhill refers to Penny as a "gorgeous 22-year-old" in "The Bath Item Gift Hypothesis" (airdate December 15, 2008), he could have simply estimated her age, as it certainly appears to be close to Christmas and the episodic events probably span days rather than weeks (if one were to ignore the hypothesis that the air date is reality in the show). In real life, the 28-year-old Cuoco is the youngest of the group, and approximately 13 years younger than Jim Parsons, who is the oldest of the group.
 * Penny has been seen naked by three of the boys, Leonard, Sheldon and Raj, so far in the series. Howard is the only person who hasn't seen her naked.
 * Leonard had relations with her multiple times in season 3, 5, 6, and 7. (Only one time in season 5.)
 * Sheldon peeked at her while trying to help her get dressed due to her injured shoulder in "The Adhesive Duck Deficiency".
 * Raj and her got undressed and had a one night stand in "The Roommate Transmogrification" (though it was revealed in the episode after that they never had intercourse at all).
 * In "The Robotic Manipulation", Sheldon calculates that Penny dated an estimate of 193 (±8) men and had relations with approximately 31 of them.
 * Penny grew up on a farm and rebuilt an entire tractor engine all by herself at the age of twelve.
 * Penny was a junior rodeo champion.
 * The previous occupant of Penny's apartment was a 200-pound transvestite named Louie/Louise with a skin condition, who worked as a police officer, according to Sheldon. He is seen during a flashback in "The Staircase Implementation", where he refers to Sheldon as 'crazy'.
 * Penny is the only member of the main set of characters whose last name has not been spoken or revealed, but Bill Prady has said it eventually will be. It will probably be revealed if Leonard and she ever get married.
 * In "Pilot," Penny claims to be a vegetarian, but will eat fish and the occasional steak.
 * Penny often smells like either vanilla (because she wears the oil) or cheesecake (because she works at The Cheesecake Factory). Sheldon has also stated in "The Decoupling Fluctuation" that she uses green, apple-scented shampoo, insisting that she switch back to that from coconut.
 * Penny's acquaintance Christy could be a reference to Kaley Cuoco's time on Charmed. Penny was also the name of the witches' grandmother. The reference may also apply to Penny's father's name, Wyatt.
 * Her beliefs in s, s,, , and other 'superstitions' (but not ) may be also be a reference to Kaley Cuoco's time on Charmed.
 * Penny eats with a fork and double-dips her egg rolls (unappealing attributes, according to Sheldon).
 * In "The Staircase Implementation", it is revealed that Penny was almost a teenage mother.
 * Penny is often kindhearted and shows empathy toward others, but can become quite fierce when provoked. She has yelled at Sheldon, Raj, and Howard when they annoy her too much, and Leonard when she's angry at him.
 * When under pain medication, Penny exhibits some of Sheldon's behaviors.
 * Penny has an amazing sense of smell.
 * Penny believes in s, s,, , and other 'superstitions', but not.
 * Penny went to, but dropped out for unspecified reasons. She goes back near the beginning of the sixth season, taking one history course. By the middle of the season, she is also taking an acting class, and at the beginning of season 7, she is taking a psychology class as well.
 * A running gag of the show involves Sheldon knocking on Penny's door and saying her name after every three knocks. He repeats this statement thrice or until she answers the door.
 * Penny often resorts to . When Sheldon's mom pointed out her disapproval of a top (shirt) belonging to Penny, she said that she had received free drinks by wearing that top. It is also known that, while she was dating Leonard, she never paid for her movie tickets. She also gets free meals from hanging with the guys since her portions were always paid by Leonard; she said they were loans, but she knew Leonard would not ask her to pay it back. She also gets free internet by using Sheldon and Leonard's -- leading Sheldon to regularly change the password to ones which accuse her of freeloading.
 * She turned down Sheldon's offer for a date (although Sheldon only asked her to make Amy jealous) as Penny was the only other woman that Sheldon knew well.
 * Penny was a in high school, making fun of a girl with a  and taping another girl up and leaving her out in a  until the next morning.
 * Penny is remarkably adept at games in general, excelling at Halo, Age of Conan, and chess, checkmating Leonard on her first try (though the latter may have been because, as Sheldon has pointed out, Leonard is terrible at chess).
 * Penny owns a red 1980s  convertible car. Featured in several episodes, the car appears to be in a bad condition, which is not helped by Penny, who pays no heed to the . While sitting in her car, Sheldon will continuously remind her that the 'check engine' warning light is on, an action that irritates Penny tremendously. Penny is a very bad driver: in "The Guitarist Amplification", a point of argument between Penny and Leonard is when Penny finds out that Leonard complains about her driving behind her back. Later in the episode, she runs a without even noticing it, and then, when Leonard mentions it, she looks back to find it, and Leonard, panicking, shouts "EYES ON THE ROAD, EYES ON THE ROAD!" She had gotten a car from Leonard in "The Friendship Turbulence" when her car broke down and she could not afford to fix it.
 * When Penny is shocked she several times while considering a reaction.
 * Over the course of the series, Penny has exhibited traits of . She is often seen drinking wine or other harder beverages while in her apartment, both alone and in the presence of her friends. She often seems to use wine as a means to deal with her issues. She will many times use this method on her friends as well to help them deal with their problems, most notably when she realized alcoholic drinks are able to help Raj overcome his selective mutism, or to help Sheldon overcome his stage fright.
 * Often says "OMG" or "Oh My God" when shocked, to the annoyance of Sheldon.
 * Despite Amy's admiration for Penny, she does realize her limitations in her intelligence and her acting career.
 * In "The Scavenger Vortex", no one wanted Penny on their team because she was a "liability".
 * Penny thinks that the wedding chapels in Las Vegas perform fake weddings.
 * Penny was unknowingly married to Zack Johnson and took his last name until the annulment.
 * In "The Adhesive Duck Deficiency", when Sheldon was dressing her, due to her dislocated shoulder, he had to put her hurt arm into the sleeve. He grabbed what he thought was her arm, but was actually her breast.
 * It was discovered by Sheldon that Penny has a Chinese character tattooed on her [right] butt cheek.
 * Though Wyatt (Penny's father) has been featured in the show, "The Maternal Congruence" references the name of Penny's father to be called "Bob".
 * So far Penny has been the only person in The Social Group to witness a Shamy kiss.
 * In the count of the number of proposals to each other, Penny has three, Leonard has three through the time they got engaged.
 * Called "Blondie" by Leslie Winkle.
 * It is rumored that Lisa Kudrow will be cast as Penny's mother.

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Penny Penny