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Melissa "Missy" Cooper is Sheldon's fraternal younger twin sister, who is ironically the direct opposite of her brother in many ways (besides being female, she is not above physical confrontation, is very charming and amicable, as well as possessing a very cheeky sense of humor). She is the sister-in-law of Amy.

Character Info

Young Sheldon

Missy is a main character. She is portrayed as a bratty, snarky and cynical 9-year-old who fights with Sheldon for attention from their parents. This pushes Georgie and her closer together, whether it's helping each other with homework, or doing favors. She and Sheldon shared a bedroom. However, she is shown to have a high EQ and comforts her brother often when she sees that he is feeling down. He does the same for her. Unlike Sheldon, Missy displayed little to no interest or aptitude in schoolwork, especially math, because she found it challenging. She watched TV the whole time she was home such as ALF, DuckTales, and Looney Tunes while ignoring her homework. The fact that she chose not to prioritize studying could foreshadow her ultimately having to work as a Fuddruckers hostess for a living while both her brothers achieved middle to upper-class standing as a physicist (Sheldon) and tire entrepreneur (George Jr.). Missy has a sweet tooth for candy. Her parents spoiled her on a daily basis by buying her sweets and letting Missy watch TV all day long. She is incredibly clever like her brothers when she wants to get her way though. The methods she uses often provides comic relief.

Season 1

She successfully pulled a splinter out of Sheldon's finger using toy tweezers, though she only did it to make Sheldon stop complaining rather than from a change of heart. (Potato Salad, a Broomstick, and Dad's Whiskey)

Season 2

Missy had given spicy gum to Sheldon, who vomits in the kitchen sink. Later, she sleeps but is kept awake by Sheldon who is disturbed by a small sound of the refrigerator. She is not happy with Sheldon who had opened up the fridge, and encourages Sheldon to receive a job as a paper boy. He encourages him to take on a paper route job, which he accepts. While Sheldon goes on the route, she follows him via car to ensure he accomplishes his task. (A High-Pitched Buzz and Training Wheels)

She later is somewhat happy that Sheldon has a peer, hoping he has a friend. (A Rival Prodigy and Sir Isaac Neutron)

One a Sunday, she overhears Sheldon wanting to visit a local Radio Shack. She was a bit talkative. Later, she was at home and watched by Meemaw while her parents attended the funeral of Stephanie Hanson's daughter daughter. In the week, she was tucked into bed by George Sr, her dad, and instead she be kissed because it was typical of Mary to do so. (A Crisis of Faith and Octopus Aliens) As usual, she is tucked in by Mary and calls Sheldon weird. Later, she noticed her mom weird as usual, and tries to confront her, but is rebuffed somewhat. (A Financial Secret and Fish Sauce)

Older Sheldon narrates that she wanted to each Sheldon’s books when they were two. Professor John Sturgis wanted Missy and Sheldon to participate in a twin study. Their parents agree to the study. Dr. Thorpe tells Missy the same purpose of the test. But before she can start, Missy makes some requests about her appearance in the video recording, ranging from the position of the camera to whether or no she has food in her teeth. She also has a few questions that are less about the test but more about the doctor; all the while, the parents watch from another room. Though Dr. Thorpe tries to get Missy to focus on the test, she briefly inquires about what she knows about the other doctor. "When you're not looking, he stares at your tushie." Connie and Dr. Sturgis are equally impressed with her over this.

When the test is over, the two doctors ask the kids how they felt about doing it. Missy is delighted to meet her own doctor, who she is very sympathetic toward. She gets some tests on empathy: a test that shows she has a lot of empathy. Dr. Thorpe appreciates her fashion advice as they are now romantically involved with one another. Mary offers Missy to select a restaurant. Much to the chagrin of George (and the delight of Meemaw), Missy selects a Red Lobster franchise, convincing him that his chance of getting a motorboat are now lost. In the evening, Missy reveals to her father that she knew money was paid and wants a share; She is tricked into asking Sheldon to do the math and get it from him.(A Research Study and Czechoslovakian Wedding Pastries)

Missy is excited for Halloween and likes how her mother is now in charg eof Heck House. She accompanies her brother, Tam, and Billy Sparks. When asked where Billy went, she points out she went out to behind a tree in order to urinate. She ended up coming to a house; the owner recognizes the fact that Sheldon is recognized as Carl Sagan. (Seven Deadly Sins and a Small Carl Sagan)

One early Friday, She is eating. Meemaw expects the kids to help with a yard sale. Missy learns about haggling from Meemaw. She uses the technique with Billy Sparks; he agrees to pay 50¢ per week for 10 weeks so that $5 is paid for a raccoon statue. (Carbon Dating and a Stuffed Raccoon)

Missy is at dinner when the phone rings. She gets up, remarks she probably is getting popular, and picks up the phone. She says is Pastor Jeff and it is for Mary. (A Math Emergency and Perky Hands)

Season 3

Season 4

Season 5

Season 6

Season 7

The Big Bang Theory

Missy first appeared in "The Porkchop Indeterminacy" (S01E15). When Leonard, Howard, and Raj find out Sheldon has a sister and that she is quite attractive, they fall over each other trying to get her attention. Raj is inspired to begin taking an experimental medication to overcome his pathological shyness. Missy is convinced to stay over with Sheldon and Leonard. Sheldon does everything in his power to ignore and avoid talking to Missy, neglecting to do anything about her being stalked and made uncomfortable by his colleagues.

Missy used to win fights by kicking Sheldon in his crotch.

When Sheldon states that he'll decide who Missy dates, she asks to speak with him privately. Sheldon reveals to Missy that she has the potential to produce a second Sheldon, even a second Sheldon that is, "taller, smarter, and less prone to freckling, a Sheldon 2.0, if you will"). Missy tells him that she is fine with him acting like a brother who cares about her, but if he tries to tell her who to sleep with, they are gonna go "round and round" like they did when they were children. This flies over Sheldon's head and he suggests Missy donate her eggs and cryogenically store them until he finds the right sperm donor to fertilize them before implanting them into her body. By this act, he suggests, "everybody wins". Missy then begins painfully squeezing her brother's testicles until he withdraws the statements.

Missy finds more of an ally with Penny, who has become slightly immune to the quartet's geekiness, as well as helping Missy extricate herself from them and lets Missy hang out in her apartment. Leonard, Howard, and Raj all knock on Penny's door to ask Missy out, but they fail in the end. When Raj goes to ask her out, she says that she was waiting for him to show up and calls him a "cutie-pie", but Raj's medication starts wearing off so he is unable to talk to her and leaves looking sad.

Before she leaves, Missy tells Sheldon that she is proud and reveals that she brags to her friends about her brother "the rocket scientist", which sparks him to correct her that he's a theoretical physicist, noting the difference. After she leaves, Sheldon mutters back to his apartment saying that being a rocket scientist is beneath him.

Sheldon mentions her in "The Jiminy Conjecture" (S3E02), when Howard, Sheldon, and Raj are trying to capture Toby/Jiminy and distinctly hear cricket chirping down the apartment building's elevator shaft. As tensions rise, Howard threatens Sheldon with, "Don't push me, Sheldon. I may be small, but I took Kung Fu when I was 13, and I remember a good deal of it," Sheldon responds with, "Oh really? Well, I grew up with an older brother and a very contentious twin sister and I believe I could easily best you in any physical confrontation, be it noogies, swirlies, or the classic 'Why are you hitting yourself?'"

Sheldon's family pedigree, depicted briefly in "The Cruciferous Vegetable Amplification" (S4E02), shows an older brother as well as his twin sister.

In "The Cooper Extraction" (S07E11), Missy is about to give birth to a baby in Texas. Since her husband is recovering from a terrible motorcycle accident, Sheldon has to go back to look after her. She does not appear on screen in this episode, only a scream as she gives birth is all that is heard from Missy.

In "The Fortification Implementation" (S8E20), Sheldon tells Amy that his brother and sister built forts in the living room and wouldn't let Sheldon in, which he hated so much.

In "The Maternal Combustion" (S8E23), Sheldon tells Leonard's mother Beverly that his brother and sister are mouth breathing idiots.

In "The Matrimonial Momentum" (S9E01), Mary Cooper mentions that since Missy is married and their brother is dating a "whore", she wants Sheldon to keep her grandmother's ring which she gave Sheldon for Amy.

In "The Meemaw Materialization" (S9E14), Sheldon reveals that he got an iPhone for Meemaw Constance as a Christmas present but she is completely unaware of it. He had Missy slip it inside Meemaw's luggage when she flew in from Texas so Sheldon could keep track of her location.

In "The Celebration Experimentation" (S9E17), Sheldon says that Missy and her friends used to torture him on their birthday and on their 6th, tricked him into believing that Batman was coming. This led to Sheldon hating his birthday and he therefore kept it a secret until "The Intimacy Acceleration".

In "The Sibling Realignment", according to George after their father died, their mother was a mess and Missy was no help because she was just a "dumb teenager".

In "The Bow Tie Asymmetry", Missy attends the wedding of her twin brother appearing physically for the first time in ten years. She is currently pregnant and separated from her husband. She is happy about the separation, but not thrilled about the baby. Amy tells her how happy she is to finally have a sister.

In "The Change Constant", she texted congratulations to Sheldon and Amy for winning the Nobel Prize in Physics.

In "The Stockholm Syndrome", in Sheldon's speech he thanked his family for all their support which included Missy.



  • She calls Sheldon by his nickname, "Shelly", as does their mother.
  • When they were kids, Sheldon turned her Easy-Bake Oven into a furnace for baking ceramic semiconductor substrates for homemade integrated circuits to make a robot to defend his room from her.
    • This would appear to create a continuity error, as Young Sheldon currently shows that Sheldon and Missy shared a bedroom. (There is the possibility that Sheldon may get his own room in a future episode, which would rectify this error, or Sheldon considers his half of their shared room a separate room from Missy's)
  • Despite their differences, Missy is very proud of Sheldon and his accomplishments, and tells people Sheldon is a "rocket scientist", which he felt deeply offended by because he is a theoretical physicist, which he views as much more prestigious and tells her that she might as well tell people that he is a toll collector at the Golden Gate Bridge.
  • When Leonard offered Missy to stay with them, she reveals that Sheldon does not like company and he used to send his imaginary friends home at the end of the day when he was a child: he denies it, saying that they were "imaginary colleagues".
  • She once had a dog who made strange noises, which she later had put down.
  • It is revealed in the Pilot that she is a hostess at Fuddruckers when Sheldon is expressing concern of "committing genetic fraud" about donating sperm at a high-IQ sperm bank ("I have a sister who has the same basic DNA mix who hostesses at Fuddruckers.")
  • In the episode "Summer Sausage, a Pocket Poncho, and Tony Danza" of Young Sheldon, it was revealed that her full first name is Melissa, Missy being a nickname.
  • Her mother dismisses her as "dumb as soup" in "The Luminous Fish Effect": though she is likely nowhere near as intelligent as her brother, she seems witty, presentable, and funny. Her oldest brother even stated he took care of Mary and Missy while Sheldon was in college, describing Missy as a dumb teenager. Though Sheldon also mentioned in "The Cooper Extraction", it took Missy six years to graduate from high school, implying her mother's comment about her intelligence isn't wholly inaccurate. Missy graduated high school when she was 19 or 20 years old. That would be the year 2000 or 2001.
  • Missy is the least successful of her three siblings, with Georgie being a self-made millionaire and Sheldon a Nobel Prize-winning scientist, while she is a divorced mother of two working as a restaurant hostess.
    • However, in fairness, she is the most attractive and socially adept of the trio. Also, since she worked as a waitress over a decade ago, there is a possiblity she could have gone forward with her life like Penny did, who was also a waitress who became a pharmaceutical sales rep using her good looks and social skills.
    • She was also the first to have children before Sheldon and Amy had at least two after their marriage.
  • When she first meets the gang at Caltech, she tells them that she spent nine months with her legs wrapped around Sheldon's head.
  • She used to obligate Sheldon to do whatever she wants by squeezing his testicles. As an adult, she still does it, but now when she gets mad at him when he suggests some absurd ideas, and if he is acting ridiculously stubborn.
  • Sheldon considers her, with his help in choosing a proper and approved-by-him mate, the future mother of a "Sheldon 2.0". As he considers himself to be a "superior genetic mutation", and with Missy being his twin sister (though still also "mediocre stock"), her DNA has great potential in producing a new version of her brother, likely even superior to him. She, however, doesn't see it that way.
  • She does recognize that "Mediocre stock" is an insult.
  • She is taller than Leonard, Penny, Raj and Howard, like her brother.
  • In one episode, Sheldon mentions that she had a guinea pig called Snowball, who ended up bursting into flames when Sheldon put him in a home-made CAT scanner.
  • Her husband's name and her son's name are both unknown.
  • Missy is the younger twin, confirmed in Young Sheldon.
  • She finally reappeared in the season 11 finale, at Sheldon and Amy's Wedding. This was her only physical appearance of her and her actress Courtney Henggeler in a decade.
  • In the episode "The Cooper Extraction", it's revealed that Missy got married and was having a baby.
    • In "The Bow Tie Asymmetry", it's revealed that she is pregnant with her second child and she and her husband are separating.
      • As shown by her sarcastic reply upon being congratulated her second child, she isn't quite thrilled about her second pregnancy.
      • Raj is shown to be delighted upon hearing Missy's separation from her husband. With him having conquered his selective mutism and experience in dating and now with Missy single, there is an indication that a possible romance may start between them. She did show interest in Raj in season 1, though this was a decade prior.
      • In "A Baby Tooth and the Egyptian God of Knowledge", it's stated that Missy ultimately ended up having a total of four children. But it was never confirmed.
  • Missy had the greatest break between physical appearances on the show with a ten-year gap for fictional characters. Ramona Nowitzki was second with a nine-year gap between appearances. Leslie Winkle has a six-year gap between appearances. Penny's father Wyatt had a five-year gap between appearances. Real-life scientist George Smoot had a ten-year gap between appearances. However, this might be debatable since she was heard once in the Season 7 episode "The Cooper Extraction" screaming since she was in labor and preparing to give birth to her son, which means that she had a 5 year-gap between her appearance in Season 1 and the Season 7 episode and a 4-5 year gap between the Season 7 episode and her second physical appearance in the Season 11 finale "The Bow Tie Asymmetry".
  • There was no appearance or mention of Missy's second child, so whether it's a boy or girl remains a mystery.
  • It is unknown what relationship she has with Sheldon's kids (her nieces and nephews).



The Big Bang Theory Episodes
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Tot
Season 1 M M 1
Season 2 M 0
Season 3 M M 0
Season 4 M 0
Season 5 0
Season 6 0
Season 7 V 1
Season 8 M M 0
Season 9 M M 0
Season 10 0
Season 11 M 1
Season 12 M M M 0


Young Sheldon Episodes
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Tot
Season 1 22
Season 2 22
Season 3 21
Season 4 18
Season 5 0
Appeared M = Mentioned Did not appear Not aired/Not available
V = Voiced C = Cameo F = Flashback I = Indirectly mentioned P = Pictured



  1. In "Pish Posh and a Secret Back Room", the adult Sheldon says: "One day she said the same thing to her first husband. I like to think I prepared her for that moment." Thus Sheldon confirmed that Missy eventually divorced with the father of her two elder children and she later remarried to another man.
  2. In "A Baby Tooth and the Egyptian God of Knowledge", adult Sheldon mentioned that his sister gave birth 4 times. This means that in addition to her eldest son and second unborn child, she will have two kids after TBBT finale.
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The Big Bang Theory Characters, Cast & Crew
Characters Main Leonard Hofstadter  ‧  Sheldon Cooper  ‧  Penny Hofstadter  ‧  Howard Wolowitz  ‧  Rajesh Koothrappali  ‧  Amy Farrah Fowler  ‧  Bernadette Rostenkowski-Wolowitz  ‧  Stuart Bloom  ‧ The Social Group  ‧ Emily Sweeney  ‧  Leslie Winkle
Recurring/Minor Debbie Wolowitz  ‧  Barry Kripke  ‧  Priya Koothrappali  ‧  Dr. V. M. Koothrappali  ‧  Mrs. Koothrappali  ‧  Stephanie Barnett  ‧  Lucy  ‧  Mary Cooper  ‧  Zack Johnson  ‧  Beverly Hofstadter  ‧  Mike Rostenkowski  ‧  Alex Jensen  ‧  Professor Proton  ‧  Missy Cooper  ‧  Ramona Nowitzki  ‧  Dan  ‧  Josh Wolowitz  ‧  Dennis Kim  ‧  Althea Davis  ‧  Jeanie  ‧  Cinnamon  ‧  Mrs. Rostenkowski  ‧  Wyatt  ‧  Claire  ‧  Kurt  ‧  Eric Gablehauser  ‧  Dave Gibbs  ‧  Dimitri  ‧  Alfred Hofstadter   ‧  Meemaw  ‧  Jimmy Speckerman  ‧  Susan  ‧  Randall  ‧  Bert Kibbler  ‧  President Siebert  ‧  Janine Davis  ‧  Colonel Richard Williams  ‧  Halley Wolowitz  ‧  Neil Michael Wolowitz  ‧  Denise  ‧  George Cooper Jr.   ‧  Larry Fowler  ‧  Anu  ‧  George Cooper Sr.  ‧  Marissa
Cast Regulars Johnny Galecki  ‧  Jim Parsons  ‧  Kaley Cuoco  ‧  Simon Helberg  ‧  Kunal Nayyar  ‧  Mayim Bialik  ‧  Melissa Rauch  ‧  Kevin Sussman  ‧  Laura Spencer  ‧  Sara Gilbert  ‧ 
Recurring/Minor Christine Baranski  ‧  Aarti Mann  ‧  John Ross Bowie  ‧  Casey Sander  ‧  Stephen Merchant  ‧  Sara Rue  ‧  Kara Luiz  ‧  Brian Thomas Smith  ‧  Margo Harshman  ‧  Alessandra Torresani  ‧  Matt Bennett  ‧  Keith Carradine  ‧  Laurie Metcalf  ‧  Judd Hirsch  ‧  Carol Ann Susi  ‧  Meagen Fay  ‧  Brian George  ‧  Alice Amter  ‧  Courtney Henggeler  ‧  June Squibb  ‧  Katey Sagal  ‧  Jack McBrayer  ‧  Dean Norris  ‧  Brian Posehn  ‧  Mark Harelik  ‧  Joshua Malina  ‧  Brian Patrick Wade  ‧  Kate Micucci  ‧  Regina King  ‧  Jerry O'Connell
As Selves Wil Wheaton  ‧  Mike Massimino  ‧  Stephen Hawking  ‧  Kip Thorne  ‧ Katee Sackhoff  ‧ Steve Wozniak  ‧ Buzz Aldrin  ‧ Summer Glau  ‧ James Earl Jones  ‧ Carrie Fisher  ‧  Brent Spiner  ‧ Howie Mandel  ‧ Bill Nye  ‧ George Smoot  ‧ George Takei  ‧ LeVar Burton  ‧ Neil deGrasse Tyson  ‧ Brian Greene  ‧ Charlie Sheen  ‧ Stan Lee  ‧ Adam West  ‧  Mark Hamill  ‧ Kevin Smith  ‧  William Shatner  ‧  Joe Manganiello  ‧  Kareem Abdul-Jabbar  ‧  Sarah Michelle Gellar
Crew Writers Chuck Lorre * (Creator)  ‧  Bill Prady * (Creator)  ‧  Steven Molaro *  ‧  Steve Holland *  ‧  Maria Ferrari *  ‧  Jim Reynolds *  ‧  Eric Kaplan *  ‧  Anthony Del Broccolo  ‧  Lee Aronsohn *  ‧  Dave Goetsch *  ‧  Tara Hernandez  ‧  Richard Rosenstock *
Directors Mark Cendrowski  ‧  Peter Chakos * (mainly as Editor)  ‧  Anthony Rich  ‧  James Burrows
Science consultant : David Saltzberg Director of photography : Steven V. Silver
Costume designer : Mary T. Quigley * Unit production manager : Kelly-Anne Lee *
Theme composer / performer : Barenaked Ladies Chuck Lorre Productions
also as Producer The Big Bang Theory : Full cast & crew on IMDb
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Young Sheldon Characters, Cast & Crew
Main Characters Main Sheldon Cooper  ‧  Mary Cooper  ‧  George Cooper Sr.  ‧  George Cooper Jr.  ‧  Missy Cooper  ‧  Meemaw  ‧  Billy Sparks
Recurring and Minor Characters Jeff Difford  ‧ John Sturgis  ‧ Tam Nguyen  ‧  Veronica Duncan  ‧  Brenda Sparks  ‧  Herschel Sparks  ‧  Victoria McElroy  ‧  Evelyn Ingram  ‧  Wayne Wilkins  ‧  Hubert Givens  ‧  Sheryl Hutchins  ‧  Gene Lundy  ‧  Tom Petersen  ‧  Le Nguyen  ‧  Trang Nguyen  ‧  Mai Nguyen  ‧  Kim-Ly Nguyen   ‧  Paige Swanson  ‧ Barry Swanson  ‧  Linda Swanson  ‧  Erica Swanson  ‧  Dale Ballard  ‧  Selena  ‧  Robin Difford  ‧  Jana  ‧  Marcus Larson  ‧  June  ‧  Grant Linkletter  ‧ Linda Hagemeyer  . Mandy McAllister
Cast Regulars Iain Armitage  ‧  Zoe Perry  ‧  Lance Barber  ‧  Montana Jordan  ‧  Raegan Revord  ‧  Annie Potts  ‧  Wyatt McClure  ‧  Jim Parsons
Recurring Matt Hobby  ‧ Ryan Phuong  ‧  Isabel May  ‧  Rex Linn  ‧  Wallace Shawn  ‧  McKenna Grace  ‧  Craig T. Nelson  ‧  Reba McEntire  .  Wendie Malick  .  Ed Begley Jr.   .  Emily Osment
As Selves Elon Musk
Crew Writers Chuck Lorre * (Creator)  ‧  Steven Molaro * (Creator)
Directors Jon Favreau
Science consultant : David Saltzberg Director of photography : Steven V. Silver
Executive Producers : Steven Molaro / Jim Parsons / Todd Spiewak Unit production manager : Kelly-Anne Lee *
Theme composer / performer : Steve Burns (performer) / Rob Cavallo (producer) Chuck Lorre Productions
also as Producer Young Sheldon : Full cast & crew on IMDb