George Cooper Sr. (Husband, deceased)
Mary is not an intellectual like her son, but is very wise, caring and sweet-natured: she is very religious and at times, can be unwittingly biggoted - something Leonard occasionally has to point out to her. She appears to be an extremely good mother and is the only one who has ever been able to control Sheldon. Leonard describes her as Sheldon's "Kryptonite". Sheldon describes Mary as being a "kind, loving, religiously fanatical, right-wing Texan, with a slightly out of scale head and a mild Dr. Pepper addiction". Sheldon has also uses his mother to exact the point that he isn't crazy, as she had him tested. Mary later confirmed the story, although with the caveat that she wished she'd "followed up with that specialist in Houston." It is shown in "The Rhinitis Revelation" that all of the gang like her very much, as she provides the attention and wisdom they did not receive from their own mothers (especially Leonard's).
She is called upon by both Leonard and Penny when Sheldon gets particularly difficult to handle.
When Sheldon is fired for disrespecting his boss, Mary comes to help when he resorts to odd activities to pass the time. At first, she tries to coax him to apologize to his ex-boss, but finally tells him off about his superior attitude and forces him to go apologize. She goes with him and Sheldon's boss, Doctor Gablehauser admittedly develops an attraction to her (she quickly points out her husband is dead). Sheldon ends up getting his job back without really apologizing.
She was mentioned in The Panty Piñata Polarization, when Sheldon banishes Penny from the apartment. Leonard, who witnessed the whole incident, decides to put an end to this war by giving Penny what he describes as Sheldon's Kryptonite: his mom's phone number. Sheldon's mother suddenly calls him and reprimands him about his behavior with Penny, she also tells him to apologize to Penny.
Sheldon goes to his hometown of Texas when he and his friends' damage his career. She welcomes him back, though she starts to irritate him with her religious quirks. The guys show up to take him back and he agrees only when his mother starts up again with her religious beliefs on evolution. She admits to being happy he is leaving, commenting, "Don't tell me prayer never works!"
Sheldon meets a new friend named Amy, who is the female version of him. They have a falling out when they disagree on whose career is better and Sheldon lapses into an odd depression where he buys multiple cats. Mary comes and tricks the two into making up by using reverse psychology: she makes it seem she is happy the two split up and they rebel by mending their friendship.
Mary comes to visit her son, but ends up spending more time with his friends. She chooses to accompany his friends on a sightseeing trip rather than go with Sheldon to a lecture where he wants to embarrass Saul Perlmutter and cook the meals that Sheldon wants her to prepare. Annoyed, he goes with Amy, but catches a cold when it rains. Becoming sick, Mary finally gives him attention and nurses him back to health.
Sheldon visits Texas when his sister is having a baby in "The Cooper Extraction". Sheldon talks with Mary on his webcam broadcast. Mary is not seen on screen, only her voice is heard.
In "The Mommy Observation," Sheldon surprises her mother with a visit and catches her having sexual relations with her boyfriend. First, Sheldon condemns her for having coitus despite her Christian beliefs and she sends him to his room. Howard, who was in Houston lecturing at NASA, tells him how he drove alway his mother's boyfriend and how she has been lonely ever since. Sheldon decides to not stand in his mother's way of happiness though he still chooses to condemn her internally. Also, he tries to have a talk with her about the birds and the bees.
"Oh, we will, you have to take your time with Sheldon. His father, God rest his soul, used to say to me, Mary, you have to take your time with Sheldon."
―Referring to Sheldon, The Luminous Fish Effect
"You know how your daddy used to say that you could only fish for so long before you gotta throw a stick of dynamite in the water? Well I'm done fishin'!"
―Talking to Sheldon, The Luminous Fish Effect
"What about you, Raj, is it? Oh, you still having trouble talking to the ladies? Because you know at our church, we have a woman who's an amazing healer. Mostly she does crutch and wheelchair people, but I bet she'd be willing to take a shot at whatever third world demon is running around inside of you."
―To Raj, The Electric Can Opener Fluctuation
- Husband: George Cooper Sr.
- Sons: Sheldon Cooper, George Cooper Jr.
- Daughter: Missy Cooper
- Mother: Meemaw
- Father: Pop-pop
- Brothers: Carl, Edward
- Grandson: Missy's child
- Laurie Metcalf was a regular in the sitcom Roseanne, along with Johnny Galecki and Sara Gilbert.
- Both Sheldon and Leonard's mothers are fit for the other: Mary for Leonard and Beverly for Sheldon.
- In "The Precious Fragmentation" Sheldon says she has a mild Dr. Pepper addiction. Her addiction to caffeine can be observed in "The Electric Can Opener Fluctuation" when she is seen drinking Pepsi.
- While not directly involving the character, In "The Cooper/Kripke Inversion", Sheldon is attempting to avoid going to work by faking illness. Leonard eventually convinces Sheldon to get dressed and get in the car by choosing similar words and a tone of voice Mary would have in the same situation. However, Leonard is unaware of why what he did was so effective.
- It was planned that she would meet Beverly Hofstadter which would have caused mother envy between the two in Season 6, but the idea was dropped when they couldn't get the actresses together at the same time.
- Sheldon wants Penny to take care of him like his mother did in "The Pancake Batter Anomaly", by singing to him and rubbing vapor Rub on his chest. He does the same thing for Amy in "The Fish Guts Displacement".