Mary (née Tucker) Cooper
Sheldon's mother, she's a very devout Evangelical Christian (whom Sheldon invariably describes as a religious fanatic) who, despite their differences, is very close to Sheldon emotionally. She is generally warm and friendly and with a southern charm that draws everyone else to love her immensely.
- Adaptation Dye-Job: She has blond hair instead of brown. It's possible that her hair either darkened over time or she dyes it brown in TBBT.
- Almighty Mom: She's the only person who can put Sheldon in his place and deal with him whenever he gets too difficult for the others to handle.
- Amazingly Embarrassing Parents: In one episode, she goes to the comic book store to confront the owner about the "inappropriate content" of the comics that Sheldon is reading.Sheldon: Mom, you're embarrassing me.
- Brutal Honesty: Not the same as Sheldon, but very blunt all in all. This seems to run in Sheldon's family.
- Celebrity Paradox: Laurie Metcalf appeared on the first three Toy Story movies (Toy Story has been mentioned many times on The Big Bang Theory). In fact, on all those movies she appeared with Wallace Shawn (who is Dr. John Sturgis on Young Sheldon, and some of his more famous roles are on Toy Story) and with Annie Potts (Meemaw on Young Sheldon) on two of them.
- The Fundamentalist: Is a strict Christian, but of the friendly variety. Her religious assumptions can be Innocently Insensitive, but she seems genuinely kind to almost everyone she meets.
- Former Teen Rebel: Stated to be such in The Big Bang Theory and is confirmed once more in Young Sheldon. In "David, Goliath and a Yoo-Hoo from the Back", Connie tells Missy that Mary used to be a rebellious teenager, but when there were complications with Missy's birth, she prayed to God and swore to become more pious and responsible, becoming the deeply religious woman she is now (or as Missy describes her, "a dud").
- Good Parents: A loving mother to Sheldon and her other children.
- Innocent Bigot: Will often say unintentionally racist comments, is frequently lampshaded.
- Mama Bear: She tells off a woman and threatens to smack her for insulting her Sheldon and tells off the principal of Sheldon's high school for wanting to expel him for being a smartass.
- Morality Pet: For Sheldon. He may be a jerk in lots of situations, but he sure loves his mommy.
- My Beloved Smother: While still a loving Doting Parent, she is often strict, overly protective and controlling, and freaks out over the smallest things Sheldon does.
- Parental Favoritism: While she claims to not have favorites, it's pretty clear she focuses more on Sheldon than her other two kids, almost to the point of Parental Neglect.
George Cooper, Sr.
Sheldon's father, a football coach who suffered from heart trouble early in Sheldon's childhood. In a moment of weakness, Sr. committed infidelity when Sheldon was young, forever staining Sheldon's view of him.
- Adaptational Nice Guy: In The Big Bang Theory, George is described as a "redneck Texas Homer Simpson" who would, among other things, drink bourbon from Pepsi cans, use dishes for skeet shooting practice and fight with Mary on a near-constant basis. While he is fond of beer and can be a little boorish at times, George is no where near that bad in Young Sheldon. This may have to do with George's infidelity having clouded Sheldon's view of his father during his early adult years, as the narrator Sheldon in this show is clearly at a later stage in life than his Big Bang counterpart and thus had time to get over it and remember George as he really was.
- Ambiguous Disorder: His alcoholism, over-eating, and overall demeanor suggest that he is secretly depressed.
- Big Eater: He has a voracious appetite and is the fattest (let alone only fat) person in the Cooper household, while ironically Sheldon won't eat enough.
- Doomed by Canon: The main show tells us he dies when Sheldon is 14, meaning his character in Young Sheldon is this.
- Henpecked Husband: In one episode he bonds with Herschel Sparks over the fact they are both bossed around by their respective wives.
- The Informant: While the details aren't made clear, it's implied that the school where he previously worked was involved in a recruiting scandal. When he went to the authorities, he ended up being fired and had to move his family to find a new job.
- It's All About Me: He can be selfish at times, emphasized in "A Computer" when he spent close to $1,000 on Lone Star beer at the expense of his own family's needs such as the computer Sheldon desired (or needed, according to Mary). Mary then hid her own money from George concerned he'll just spend it on more beer.
- Jock Dad, Nerd Son: As a football coach (in Young Sheldon), he's the Jock Dad to Sheldon's Nerd Son.
- Laser-Guided Karma: After George Sr. cheated on his wife, she kicked him to the curb, and George later died due in part to a negligent attitude toward his health after a scare with a near-fatal heart attack.
- Not So Above It All: He has a bit of a penchant for gossip. A few episodes have him listening to Missy's gossip and loving every bit of it.
- Obfuscating Stupidity: In one episode, Sheldon admits that he only realized years later that his father would often pretend to be dumb just to cheer him up and make him feel better ("My brother, on the other hand, didn't have to pretend").
- Only Sane Man: While he's not a genius and borders on Bumbling Dad at times, he's the most normal member of the family and the one with the least excessive behavior, compared to Mary, Georgie, Missy, Sheldon, and especially Meemaw. Taken Up to Eleven in "A Math Emergency" when he sees Sheldon, Dr. Sturgis and Meemaw all argue about quantum chromodynamics as while Mary leaves dinner to go visit an elderly hermit for religious purposes, George pauses to ask, "The hell is going on today?!" This situation is bombastic enough to make George stop eating.
- Papa Wolf:
- To Sheldon. When he becomes physically sick over his obsession to prove a NASA scientist wrong after he brushed him aside, George drives him and his family all the way to Houston, barges in his office, and demands that he listen to his son.
- He also punches out Clint (Veronica's mother's boyfriend) for putting his hands on Georgie.
- Parental Neglect: A downplayed example who only sometimes gets it right as a dad, but shows a lot of indifference or annoyance toward big things and defers to Mary or Meemaw and can be rude and unhelpful at times and just not wanting to be bothered with a lot of BS. Adult Sheldon once remarks, "My sister bought my dad a 'World's Greatest Father' coffee mug, and frankly, he just coasted all the way until the day he died."
- Parents as People: George may show a bit of Parental Neglect at a time, but he ultimately cares for his family as shown by his various Papa Wolf moments. Adult Sheldon even admits later he didn't realize all he really did for him until later.
- Pursue the Dream Job: He wants to be a college coach again, but is forced to give up the dream to coach at Tulsa despite how good the offer is simply because the rest of the family didn't want to move.
- Straw Misogynist: He once told Sheldon that a woman's sexual appeal and fertility last as long as an egg salad sandwich on a hot day.
- Sympathetic Adulterer: It's hard not to feel for George when you consider how much of a basket case and neurotic Bible-beater Mary could be, and George being driven to have a romance with someone more sane.
- Trademark Favorite Food: He loves Lone Star beer and Meemaw's brisket.
- Your Cheating Heart: Sheldon later explains the reason he knocks three times is because he caught his dad in bed with another woman when he unwittingly opened the door to the bedroom.
George "Georgie" Cooper, Jr.
Sheldon's not-too-bright older brother.
- Beauty, Brains and Brawn: Dumb Jock Georgie is the brawn to Sheldon's brains (Insufferable Genius) and Missy's beauty (what she'll grow up to be).
- Big Brother Bully: Downplayed. He's openly dismissive of Sheldon but most of the time he just ignores him. According to Sheldon himself, Georgie is often mean to him and apparently breaks wind on his head.
- Black Sheep: Clearly the most infamous member of the Cooper brood next to Meemaw. Even when he was little, everyone is sure George Jr. will become this to the family into his childhood when he acts like a total numbnut with no common sense, and Sheldon later mentions he got thrown in jail and went to court for peeing in a phone booth.
- Brilliant, but Lazy: The real reason everyone thinks he's dumb. Even while he was still young and apparently not-too-bright, he displayed wisdom beyond his years every now and then, and it says a lot that Missy goes to him for help with homework and, once he decides to focus and properly help her, he manages it. He just had no interest in applying himself and felt comfortable with being a stereotypical jock.
- Captain Obvious: Georgie tends to make statements that are fascinating to him but obvious to everyone else, including his realization that E.T.'s human friend Elliott has a name starting with an E and ending with a T.
- Dogged Nice Guy: Has this relationship with his crush, Veronica Duncan, who is clearly not interested in him beyond friendship.
- Dumbass Teenage Son: He's a teenager and clearly considered stupid by all his family members who are often vocal about it.
- Dumb Jock: He is not particularly intelligent (compared to Sheldon, at least) and plays on the football team.
- Foolish Sibling, Responsible Sibling: The Foolish (along with Missy) to Sheldon's Responsible. Sheldon was always an extremely smart goody two shoes while both his siblings are Book Dumb and careless.
- Hidden Depths: He is insecure about not being as smart as Sheldon and is also jealous of the attention his younger brother gets. When his father had a heart attack, he was so overcome with worry, he stole Meemaw's car and drove him and his siblings to the hospital. He also shows a hint of maturity when he called out his father for his racism.
- Love Redeems: Although it starts as a rather blatant act to appeal to Veronica's newfound Christian-friendly tastes, Georgie gradually really improves.
- The Un-Favourite: In one episode Sheldon starts breaking rules because, in his own words, he was trying to be more like Georgie. His parents reply, "We don't want Georgie to be like Georgie".
Melissa "Missy" Cooper
Sheldon's fraternal twin sister and his polar opposite.
- Adaptational Dye Job: The present-day adult version has dark brown hair, but the Young Sheldon version has dark blonde hair.
- Adaptational Jerkass: In Young Sheldon, Missy is much less of a nice character than in The Big Bang Theory. Little Missy was a near-complete Bratty Half-Pint who started cussing before she hit double digits and loved to antagonize Sheldon and get her way, but could still be nice. It's a backpedaling away from her present-day maturity to show that she used to be a real stinker.
- Aww, Look! They Really Do Love Each Other: While she is regularly annoyed by Sheldon, she actually starts to miss him when he is sent to live with a couple so he can attend a school for gifted students, and is overjoyed when he comes home. She also slept in Sheldon's bed when he had to spend several nights in the hospital following a gallbladder surgery. Also, despite her desire to make fun of Sheldon, she will comfort him in times when he is genuinely upset.
- Beauty, Brains and Brawn: She is the beauty (especially as an adult) to Georgie's brawn (Dumb Jock) and Sheldon's brains (Insufferable Genius).
- Berserk Button: Messing with her Cabbage Patch doll Celeste. In an attempt to use negative reinforcement to influence Missy's behavior, Sheldon cuts a single strand of yarn off the doll's head, and Missy gives him a black eye in return.
- Bratty Half-Pint: She openly insults and messes with her two brothers and is even rude to her own mother. She is aware of her own bad attitude, such as when Mary angrily asks her why she is such a brat and she claims she is "crying for attention."
- Dumb Blonde: Missy has dirty blond hair in this show and is quite ditzy. Academically, at least.
- Everyone Has Standards: She loves to tease and insult Sheldon, but she can't bring herself to do so when he's crying and immediately rushes to hug him.
- Foolish Sibling, Responsible Sibling: The Foolish (along with Georgie) to Sheldon's Responsible. Sheldon was always an extremely smart goody two shoes while both his siblings are Book Dumb and careless.
- Freudian Excuse: It is implied that her snarky remarks and bratty attitude are her way of trying to get attention since her parents are almost always focused on Sheldon than her and Georgie.
- Girly Bruiser: Likes dressing up and playing with dolls, but is more than willing to resort to violence if you piss her off.
- Jerk with a Heart of Gold: She's very much a rude, sarcastic and foul-mouthed little girl, but she is capable of compassion.
- Little Miss Snarker: She was every bit as snide and sarcastic as a child. Being Sheldon's twin, she had to start early.
- Not Even Bothering with the Accent: Adult Missy has a Texas drawl. Young Missy, however, does not.
- Polar Opposite Twins: With Sheldon. Sheldon is book-smart, naive, only interacts with others when forced to and tends to look down on anyone who isn't as smart as he perceives himself to be. Missy is an outgoing Street Smart underachiever.
- Sibling Yin-Yang: Aside from their similar physical features, Missy and Sheldon are literally polar opposites in personality and behavior.
- Skewed Priorities: In one episode, she tried to ignore an emergency tornado warning on TV that was interrupting Looney Tunes.
- The Slacker: She spends her entire day at home watching TV and eating candy.
- The Social Expert: Missy is very socially perceptive, to the point she impresses a team of scientists studying various types of intelligence in twins.
- Spoiled Brat: Her parents let her watch TV all day, eat candy and don't really do anything to stop her from harassing Sheldon or Georgie.
- Troubling Unchildlike Behaviour: She's often way too aware about things inappropriate for her age. And when she hears about an incoming tornado, she complains that doesn't want to die because she's only kissed one boy.Missy (seeing Mary's horrified expression): 'Relax, it was a long time ago!'George Sr.: 'Are you relaxed?'
Constance "Connie" Tucker
Sheldon's maternal Grandmother, whom he calls "Meemaw"
- The Alcoholic: Alluded to. Sheldon serves her whisky as she likes it, "A lot in a glass."
- And Starring: "with Annie Potts".
- Cool Old Lady: In the episode "Poker, Faith and Eggs" she gives Missy a guitar, George Jr. firecrackers, and plays poker with Sheldon while babysitting them.
- Celebrity Paradox: Annie Potts appeared on the first two Toy Story movies (Toy Story has been mentioned many times on The Big Bang Theory.) In fact, on all those movies she appeared with Wallace Shawn (who is Dr. John Sturgis on Young Sheldon, and some of his more famous roles are on Toy Story) and with Laurie Metcalf (Mary on Theory).
- Commitment Issues: She turns down Dr. Sturgis' marriage proposal on the grounds that she has no desire to get married again. Though considering that her first husband died a long time ago, it's implied that she doesn't want to deal with that pain all over again.
- Deadpan Snarker: She she never misses a chance to snark at the rest of the family, especially George Sr. and George Jr.
- Dirty Old Woman: Has this attitude, sometimes even making sexual jokes in front of the children, much to Mary's embarrassment.
- Doting Grandparent: She dotes on Sheldon and is also close to her other grandchildren.
- Enemy Mine: In spite of her cold relationship with George Sr., they often band together to properly parent Sheldon whenever he acts rambunctious.
- Grandma, What Massive Hotness You Have!: She's very attractive for her age, and attracts a decent number of men, including Dr. Sturgis (as well as a rival colleague of his) and Ira Rosenblum.
- Jerk with a Heart of Gold: She's blunt, irresponsible, and sometimes rude, but is also a loving grandmother who always tries to understand Sheldon's needs.
- Love Triangle: Connie Tucker, John Sturgis and Ira Rosenbloom.
- Mama Bear: She's extremely protective of Sheldon, especially when someone says something bad about him.
- Morality Pet: To Sheldon who is genuinely devoted to her. Along with his mother, she's one of the few people Sheldon is nice to.
- Never Mess with Granny: In the episode "A Dog, A Squirrel, and a Fish named Fish", she gets into a fight with the Coopers neighbor Brenda (and wins) after Brenda calls Sheldon "weird".
- Obnoxious In-Laws: To George Sr. She feels he's not good enough for her daughter. Though there are times when they get along quite well, sometimes making jokes together at Mary's expense.
- Secret Ingredient: Connie makes a delicious brisket, and refuses to give George the recipe.
- Wacky Parent, Serious Child: The foul-mouthed, alcohol-loving, wacky mother to her conservative, religious daughter Mary.