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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 on Young Sheldon. She is portrayed as a bratty, snarky and jaded 9-year-old who fights with Sheldon for attention from their parents. Sheldon gets all the attention because of his intelligence and for starting high school at such an early age. This pushes Georgie and her closer together, whether it's helping each other with homework, or doing favors. Missy is often disrespectful and contemptuous towards Sheldon, wishing him to disappear and even showing signs of optimism when her parents considered getting a divorce, hoping she could get away from Sheldon and part with her mother (she was annoyed when Sheldon also wanted to be with Mary). She relished seeing Sheldon have bad luck and being lonely at school, although she always ends up on his side. She and Sheldon shared a bedroom. In "Potato Salad, a Broomstick, and Dad's Whiskey", 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. 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. Despite being closer to her older brother Georgie, (although this closeness is one-sided and she frequently enjoys him suffering) she prioritizes family and helps Sheldon win the student body president debate.

She later finds an interest in baseball, which she only learned, in the beginning, to impress a boy she had a crush on, but learns that she has a true talent in it. Missy is incredibly headstrong, as shown when the other boys in baseball give her trouble but she deals with it very effectively. Because her mother seems to show more of an interest in Sheldon's welfare, she bonds with her father, who often takes to baseball practice and shares her personality, cheering her on along with her grandmother as she beats up a boy who mocked her in baseball.

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.

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. 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 who is currently the only one with children. Also, since she worked as a waitress over a decade ago, there is a possibly 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.
  • 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 1 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.
  • 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.
  • 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. This was offscreen, but it was never confirmed.



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 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



v · e · d
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  ‧  Emily Sweeney (formerly)  ‧  Leslie Winkle (formerly)  ‧  The Social Group
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
v · e · d
Young Sheldon Characters, Cast & Crew
Main Characters Main Sheldon Cooper  ‧  Mary Cooper  ‧  George Cooper Sr.  ‧  George Cooper Jr.  ‧  Missy Cooper  ‧  Meemaw  ‧  Jeff Difford  ‧  Billy Sparks
Recurring and Minor Characters 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   ‧  John Sturgis  ‧  Paige Swanson  ‧ Barry Swanson  ‧  Linda Swanson  ‧  Erica Swanson  ‧  Dale Ballard  ‧  Selena  ‧  Robin Difford  ‧  Jana  ‧  Marcus Larson  ‧  June  ‧  Grant Linkletter  ‧ President Hagemeyer
Cast Regulars Iain Armitage  ‧  Zoe Perry  ‧  Lance Barber  ‧  Montana Jordan  ‧  Raegan Revord  ‧  Annie Potts  ‧  Matt Hobby  ‧  Wyatt McClure  ‧  Jim Parsons
Recurring Ryan Phuong  ‧  Isabel May  ‧  Melissa Peterman  ‧  Billy Gardell  ‧  Valerie Mahaffey  ‧  Danielle Pinnock  ‧  Doc Farrow  ‧  Brian Stepanek  ‧  Sarah Baker  ‧  Rex Linn  ‧  Wallace Shawn  ‧  McKenna Grace  ‧  Craig T. Nelson  ‧  Ava Allan  ‧  Jason Alexander  ‧  Reba McEntire  ‧ Ed Begley Jr.  ‧ Wendie Malick
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