A Vietnamese teenage boy who was also the childhood friend and classmate of Sheldon Cooper. Tam is Sheldon's only friend.
- Asian and Nerdy: He's the one who introduces Sheldon to comic books and role-playing games for the first time.
- Broken Bird: Somewhat sullen and pessimistic because of his Dark and Troubled Past. He appears to have PTSD.
- Casanova Wannabe: Look at one of the reasons his and Sheldon's friendship with Libby broke up: because Tam tried to hit on her when they went without Sheldon to that IMAX movie and she didn't like it.
- Composite Character: Seems to be an amalgamation of the friends of adult Sheldon. He is the best friend of Sheldon in Texas while Leonard is Sheldon's best friend in California and both serve as the straight man to Sheldon's funny man. Like Howard, Tam hits on every girl he meets. Tam and Raj are both foreigners and Mary Cooper's racially insensitive comments to both are quite similar.
- Dark and Troubled Past: After the Vietnam War, Tam's father was sent to a reeducation camp because he fought with the Americans. Meanwhile, his mother, his sisters, and he lived in poverty and sometimes starved. After his father was released, they reunited and fled to Thailand and were forced to live in a refugee camp. Eventually, they left for the United States and settled in Galveston. His father bought a shrimp boat and started a business until the KKK burnt his boat and chased away his family.
- Defector from Commie Land: Tam's family were among the "boat people" who fled Vietnam after the war.
- Doomed by Canon: By the time of The Big Bang Theory, Sheldon and Tam are no longer friends, and Tam wasn't mentioned for a long time. It's finally revealed that Tam had planned to go to college with Sheldon, but ended up staying in Texas with a girl he was dating. Sheldon felt so betrayed that he didn't contact or mention him for many years.
- Earn Your Happy Ending: He suffered through poverty in Vietnam and often having an abusive childhood from his parents after moving to the United States. When he finally appears in The Big Bang Theory he is Happily Married, has one son and least one other child, and eventually repairs his friendship with Sheldon. He himself even describes his life has been great, a stark contrast to how his home life sounded in his childhood.
- Extraverted Nerd: He tries so desperately to hang with the cool crowd and date hot chicks. And he fails miserably every time.
- Hypocrite: He denounces US action in Vietnam calling the Americans the "wrong side", but he fled to the United States to escape Vietnam for a better life.
- Intergenerational Friendship: Downplayed, but Tam is at least five years older than Sheldon. He also occasionally hangs out with Missy and Billy.
- Only Friend: To Sheldon, in his childhood. (Except for that brief time when Libby was also their friend, as well as Sheldon's brief and brief and one-time friendship with George Jr.'s bully Tommy Clarkson.)
- Out of Focus: He has appeared less often in season three so far, appearing in only three episodes.
- Reduced to Ratburgers: He mentioned eating only pigeons and rats while fleeing Vietnam.
The son of a neighbor to the Cooper family.
- Abhorrent Admirer: He has a one-sided crush on Missy.
- Adaptational Nice Guy: Sheldon describes him as a bully in The Big Bang Theory but in Young Sheldon, he's on friendly terms with Sheldon and it's actually Billy's sister Bobbi who bullies Sheldon.
- Ambiguous Disorder: Billy's low intelligence is Played for Laughs, but he's likely mentally handicapped in some way.
- The Bully: To Sheldon, but only in the pilot. After that, his little sister Bobbi takes on the bully role.
- Characterization Marches On: In his first appearance he is indeed shown bullying Sheldon, calling Sheldon a doofus and taunting him with his pet chicken Matilda. After that, Billy quickly becomes more of an emergency playmate/underling figure to Sheldon.
- Dumb Jock: He's on the same baseball team as Missy, and spent practice eating dirt and playing with worms.
- Fat Comic Relief: He's a tubby, idiotic kid whose actions are Played for Laughs.
- Fat Idiot: He's a slow and overweight kid who often says and does stupid things.
- Nice Guy: Pilot aside, Billy is a friendly boy and he and Sheldon are on civil terms. They even occasionally spend time together.
- Not So Different: Billy, like Sheldon, is considered a weirdo and doesn't have a lot of friends. His mom Brenda doesn't want to invite Sheldon to Billy's birthday party because she worries that hanging out with Sheldon will make Billy even less popular, only doing so after Mary convinces Pastor Jeff to guilt-trip her in his sermon about being neighborly.
A troubled teen who becomes a Born-again Christian. She is the object of Georgie's affection.
- Beware the Nice Ones: Being a born-again Christian didn't stop her from giving Georgie a black eye in retaliation for kissing her without permission during their baptism.
- Dark and Troubled Past: She was abandoned by her father and her older sister is in prison for trying to sell drugs to a cop.
- Disappeared Dad: As mentioned above, her father left when she was very young and her mother's boyfriend as a drunken jerkass.
- Doomed by Canon: Given that Veronica isn't with adult Georgie in The Big Bang Theory, any romance that may happen between the two will have ended before their adulthood. Adult Sheldon confirms that Georgie has two ex-wives, marrying the first when he was 19, so it's possible that Veronica might be his first wife.
- Earn Your Happy Ending: Adult Sheldon's narration at the end of "Seven Deadly Sins and a Small Carl Sagan" indicates that Veronica went on to live a life devoted to God and help feed the poor, even helping her older sister, who she said previously had been arrested, start a literacy program for female inmates.
- Easy Evangelism: After visiting Mary Cooper's Hell house on Halloween, she ends up immediately embracing Christianity upon seeing the sin of Lust.
- Easily Forgiven: She's rather quick to forgive Georgie for coming on to her during their baptism. Perhaps justified due to her religious beliefs.
- Friend to All Children: She wants to be a teacher as she likes kids and gets along with Missy and Sheldon rather well.
- Girly Bruiser: Very sweet and feminine, but capable of giving Georgie a black eye with one punch.
- Hair of Gold, Heart of Gold: She has blond hair and is very nice and compassionate to all, even Georgie.
- Let's Just Be Friends: Georgie has a big crush on Veronica and the two even date on Halloween. Though after embracing God, Veronica would rather be friends. Though she seems to be developing feelings for him as of "A Proposal and a Popsicle Stick Cross".
- Nice Girl: She is a very nice and compassionate person and a delightful person to be around.
- Really Gets Around: Heavily implied to be this before her salvation, as Sheldon notes that there are a lot of boys she has been "friendly" with. Had it not been for the visit to the Hell House, Veronica and Georgie would have likely ended up having sex on Halloween.
- Statuesque Stunner: Very beautiful and taller than Georgie.
A Child Prodigy who takes Dr. Sturgis' class alongside Sheldon. She's not only smarter than Sheldon, but also more social as well. Sheldon views her as a rival, but Paige is always kind towards him.
- Always Someone Better: And this is why Sheldon views her as a nuisance. She's not only more intellectually gifted (for one, she's fluent in three languages while Sheldon only knows English and some Spanish, along with conversational Klingon.) but has better social skills as well. And she is a month younger, making her both the youngest and smartest person in Dr. Sturgis' class.
- Delinquent Hair: Sports a new hairstyle with pink highlights in "Body Glitter and a Mall Safety Kit". And the hair isn't just for show, as Paige has also become a lot meaner (at least away from the adults), more sarcastic and even steals a bottle of body glitter from Hot Topic and sneaks it out in Sheldon's backpack.
- Five-Finger Discount: She and Missy want to buy some body glitter at Hot Topic, but neither have any money. They try to steal it, but Sheldon catches them in the act and they back down. Then Paige sticks it in Sheldon's backpack when he turns away to leave the store.
- Given Name Reveal: Her last name was never stated in her first three appearances, but "Body Glitter and a Mall Safety Kit" confirms that her last name is "Swanson."
- Glomp: Gives one to Sheldon. Sheldon, who Hates Being Touched, reacts the way you'd expect.
- Hair of Gold, Heart of Gold: Despite sharing Sheldon's academic intellect, she is much friendlier and more social.
- I Just Want to Be Normal:
- Subverted. In her debut episode, she asks Sheldon if he sometimes wishes he was normal, but Sheldon says no and Paige says the same, as she enjoys being smarter than everyone else.
- Double subverted by "Body Glitter and a Mall Safety Kit". Sheldon asks Paige why someone as smart as her would resort to shoplifting. She tells Sheldon that she doesn't want to be smart anymore. Sheldon, of course, can't comprehend why Paige would say this and he calls Dr. Sturgis for advice on how to handle it. John tells Sheldon that the best thing to do would be to just listen to her problems. It turns out that Paige blames herself for her parents splitting up, as they had a hard time dealing with her needs. She also cannot cope with all the sudden changes in her life, which is why her grades have been slipping and why she's been acting out.
- Innocently Insensitive: She has a tendency to insult Sheldon's intelligence, though usually not intentionally. She doesn't do this to Missy, mainly due to the two having common interests outside of science.
- Innocent Prodigy: Despite sharing Sheldon's academic intellect, she likes My Little Pony, Hello Kitty, playing with dolls, and has a childish, mischievous side.
- Intelligence = Isolation: Ultimately subverted. She tries to befriend Sheldon but he has no interest in making friends with a girl who (unintentionally) keeps insulting him for not academically catching up to her speed, proving that just like Sheldon, Paige doesn't know how to avoid offending other people and she implies that she doesn't have a lot of friends because of this. Though in "A Stunted Childhood and a Can of Fancy Mixed Nuts" she is able to form a friendship with Missy due to them having the same interests outside of science and Paige is able to avoid talking down to Missy despite their gap in intellect (for example, she didn't mock Missy for not knowing where tea comes from, which is something Sheldon would have leaped at the chance to do). This is in contrast to Sheldon, who is not interested in socializing with others and isn't shy about expressing his perceived intellectual superiority over others.
- Karma Houdini: She gets no comeuppance for shoplifting the body glitter in "Body Glitter and a Mall Safety Kit".
- Manipulative Bitch: In "Body Glitter and a Mall Safety Kit", she's able to guilt trip Mary into taking her, Missy and Sheldon to the mall, which is something Mary usually wouldn't do (Mary says it's because the mannequins don't wear enough clothes, but Missy and Sheldon know it's because they're too poor to shop there). In fact, Paige says to Missy that ever since her parents split up, people just can't say "no" to her and she takes full advantage of it.
- Nice Girl: Unlike Sheldon, she is very sweet and kind.
- Oblivious to Hatred: Downplayed. She is aware that Sheldon doesn't like her much, but that doesn't stop her from trying to be friends with him because she read in a psychology magazine that children who don't socialize often grow up to become weirdos. This is why she makes attempts to goof off like other kids and why she insists on spending time with Sheldon, as she doesn't want him to grow up being hated and lonely.
- Odd Friendship: She befriends Missy when Sheldon stops paying attention to her. Despite their differences in intellect, they have the same girly interests and get along without any tension.
- O.O.C. Is Serious Business: Sheldon is able to recognize that Paige's drastic change in appearance and behavior is a reflection of some inner problems and calls Dr. Sturgis for help.
- Took a Level in Jerkass: Her return in the episode "Body Glitter and a Mall Safety Kit" sees her taking on a new "bad girl" look and acting out as a way of coping with her parents' divorce. Though she's still a good person deep down. Something that Sheldon of all people is able to see.
- Toxic Friend Influence:
- She encouraged Sheldon to wander through a museum with her when they were supposed to be listening to a lecture (they both already knew everything that the lecturer was teaching, but Sheldon was determined to power through it to obey his father's command to stay put). They end up getting in trouble for messing with the displays. It's hinted in "A Stunted Childhood and a Can of Fancy Mixed Nuts" that she's trying to help Sheldon break out of his shell so that he won't grow up to be socially stunted. Obviously, she doesn't succeed.
- She also encourages Missy to shoplift at the mall Missy objects to it, so Paige just does it herself.
- Vocal Evolution: Her voice is noticably lower-pitched in "Body Glitter and a Small Safety Kit", due her previous appearance in the series taking place over a year ago in real-time, allowing Mckenna Grace to start puberty.
Sheldon's homeroom teacher and English teacher at Medford High School
- Big Eater: She stress eats out of depression over gender inequality, claiming this as the reason why she's not the school principal. Though she's not overweight (yet).
- Formerly Fit: Sheldon's narrations imply that she will become obese in the future as a result of her eating habits.
- Hypocrite: She complains that she wants to live long enough to see women no longer treated like second-class citizens while munching on a chili cheeseburger, high in trans fats and calories.
- Straw Feminist: As she put it, she wants women to no longer be treated like second-class citizens.
- Trademark Favorite Food: Chili cheeseburgers.
Sheldon's P.E. teacher and assistant football coach at Medford High.
- Black Best Friend: To George Sr.
- Happily Married: George is somewhat jealous over how much better Wayne's marriage seems to be than his own. Until he realizes that Wayne and his wife don't have any children.
- Hypocrite: He tends to give others health advice despite not being in very good shape himself.
- One example comes from "An Eagle Feather, a String Bean and an Eskimo", where Sheldon points out how hypocritical is of him to ask his students to run twenty laps when he is not willing to lead by example.
- In "A Proposal and a Popsicle Stick Cross", he encourages George not to eat a donut for health reasons. Though to be fair, George has had a heart attack.
- Like an Old Married Couple: Has this relationship with George, even saying he considers himself to be George's "work wife".
- Sensitive Guy and Manly Man: Wayne is the sensitive guy to George's manly man. Wayne takes on the stereotypical "female" role in their Like an Old Married Couple relationship. He also mentions that his dad was a hugger.
- Sudden Name Change: His first name was initially "Roy", but in "A Broom Closet and Satan's Monopoly Board", it was changed to "Wayne."
A physics professor at East Texas Tech, the university Sheldon is auditing coursework for, and is dating Meemaw. Specifically, Sheldon is learning quantum chromodynamics in Sturgis's class.
- Adorkable: He's as socially unaware as Sheldon, but is nicer and has more of an awkward charm about him that makes Connie fall head over heels for him.
- Ambiguous Disorder: He was sent to a mental hospital after having a breakdown at the end of season 2, and this wasn't the first time he had one. It's never specified exactly what's wrong with him, though given his age, it could be some form of Dementia.
- Celebrity Paradox: Wallace Shawn appears as Dr. John Sturgis. Shawn's most famous roles are in The Princess Bride and Toy Story, both of which have been mentioned many times on The Big Bang Theory. In fact, on Toy Story, he appeared on the first two movies with Annie Potts (Meemaw on Young Sheldon) and on the first three with Laurie Metcalf (Mom on Theory). More indirectly, he was Grand Nagus Zek on Star Trek: Deep Space Nine, which is a Spin-Off of Star Trek: The Next Generation. Well, of course, Wil Wheaton was Wesley Crusher on Next Generation and also was on Theory As Himself.
- Doomed by Canon: Seeing as how he doesn't appear nor is referenced in The Big Bang Theory, his romance with Connie is this. It's likely that either he'll die at some point or they will eventually break up. It seems to be the latter though as John broke up with her in the Season 3 episode "A Pineapple and the Bosom of Male Friendship".
- Friendless Background: He didn't have much of a social life before meeting the Cooper family. This is likely why he continues to hang with them even after he broke up with Connie.
- The Friend Nobody Likes: Outside of Sheldon and Connie, the Cooper family don't seem to like him very much. Missy is the most vocal about it, though it's implied that she's angry at him for breaking Connie's heart. George takes him out for drinks a few times at Mary's urging and doesn't seem to enjoy it much, but feels guilty enough for shooting him down to invite John over to watch a football game. Georgie seems to at least tolerate John, and being the person he is, asks uncomfortable questions that John is more than willing to answer.
- Friendly Rivalry: With Ira Rosenbloom for Connie's love, after getting to know one another at the Rosenbloom furniture business.
- Gender-Blender Name: His middle name, Whitney. From the scene when Connie (Meemaw) finds out about it:John: My middle name's Whitney.Connie: And now I know that.
- Love Triangle: Connie Tucker, John Sturgis and Ira Rosenbloom. Later Connie and John with Coach Dale Ballard.
- Manchild: Despite his old age, he's just as, if not even more childish than Sheldon is. He steers a bike instead of a car, wears elbow patches and overprotective gear while bicycling, and is reluctant to do things on his own without asking permission from Meemaw as if Meemaw is his mother.
- Nice Guy: He is very kind-hearted and one of Sheldon's closest friends. He also happens to be the only one of Sheldon's teachers who gets along with him and is fond of Sheldon.
- Scatterbrained Senior: The season 2 finale implies that he is becoming senile in his old age, and by season 3, he has been checked into a mental institution.
- Sudden Name Change: He stated in his debut episode that his middle name is "Whitney", but in "A Perfect Score and a Bunsen Burner Marshmallow" he says his middle name is "Burgess". To be fair, he was delirious at the time, but it was more likely a Series Continuity Error.
- Ugly Guy, Hot Wife: Dr. Sturgis looks like a human-turtle, yet his awkward charm was enough to woo Connie.
- Yes-Man: He does everything and anything Sheldon and Meemaw ask him to do with eager compliance. Taken Up to Eleven in S2E18 when he even agrees to have Sheldon live with him at his house, but it turns out Sturgis is horribly incompetent to take care of a child as he had no idea how to handle emergencies when his kettle pot caught on fire and he had to call 9-1-1.
The pastor at the church Sheldon and his family attend. Also gives Sunday school to Sheldon, his sister, Billy Sparks and other kids. Had an Hispanic wife, Selena, played by Zuleyka Silver.
- Ascended Extra: As of the Season 3 premiere "Quirky Eggheads and Texas Snow Globes", he billed as part of the main cast.
- Awful Wedded Life: Proved to some extent by Selena not knowing Jeff's actual finances and he having to mistranslate what she says to the Cooper family. The plot of season 2's "A Broken Heart and a Crock Monster" is about Pastor Jeff moving in with the Coopers after he and Selena stopped speaking to each other and he starts sleeping on his office's couch. By the end of the episode, she dumps him because he is "un perdedor" (Spanish for "a loser").
- Credit Card Plot: His wife's dealings with a massage chair salesperson.
- The Fundamentalist: He tries to convert everyone, including atheists such as Sheldon, to Christianity. While it's unknown how many he's converted to Christianity, he's failed miserably to do so with Sheldon.
- Henpecked Husband: In the episode Selena dumps him, he's actually so afraid of her coming at him with a cutler's knife he goes to his home accompanied by Mary.
- Insane Troll Logic: Sheldon interprets Jeff's defense of religion as being this, such as the fact that Charles Darwin is right about God but wrong about evolution. Sheldon also disproves Jeff's theory there's a 50/50 chance of a god existing, arguing all probability in the already-existing universe (not a theoretical one) must be taken in a binary sense (0 or 1) making the chances 100/0 rather than 50/50.
- Mistaken for Pedophile: In "A Crisis of Faith and Octopus Aliens", Mary's struggling to cope with the death of a neighbor girl. Jeff advises her to go help the needy, start a Bible study, or hug a stranger and tell them God loves them. As long as it's not a child, as that backfires.
- Mock Millionaire: Lied about his wealth to Selena. It's clear he has a very precarious financial status.Mary: Why don't you just talk to her? Explain your financial situation?
Mary: Oh, we're closing the door now, okay.
Jeff: That's not so easy.
Mary: Because of the language barrier?
Jeff: That, and I implied, when we were dating, that I was well-to-do.
- Nice Guy: Despite his flaws, he cares about everyone and tries to be the best Christian he can.
- Religion Is Right: The viewpoint Pastor Jeff tries to impart on his audience (without necessarily saying Science Is Wrong although at times it may seem so) during Sunday school and Sunday service. Unfortunately Sheldon is present at both, and pokes holes in his arguments.
- Tactful Translation: It's obvious he actually knows Spanish, but he's purposely mistranslating Selena to the Cooper family due to Selena's pessimism. Unfortunately, Sheldon, who does know the language, is there and thinks he doesn't know it.
- Trophy Wife: He once described Selena like this after being asked by Mary Cooper:Mary: Oh, Pastor Jeff, why would you do that [lie about his finances]? You saw her.
Jeff: Uh, she is the kind of woman that can make a man do bad things.
- Ugly Guy, Hot Wife: While not ugly, he's definitely a dorky-looking (and dorky-acting) guy married to a total knockout. Though she's a Gold Digging bitch who leaves him. But then he ran into a Fair Cop who had just moved to town and was very into him.
A professor and colleague of Dr. Sturgis. He constantly tries to woo Connie away from him, to no avail. Sheldon audits his course during John's recovery.
- Hopeless Suitor: He regularly pursues Connie, even though he knows she's with John, and fails miserably every time.
- Jerkass: If coming on to another man's girlfriend in front of said man isn't enough to qualify him as this, he also regularly uses Sheldon to get closer to Connie, allowing Sheldon to take his class while John is recovering at the mental hospital, asking Connie to an event in front of Sheldon so that she can't say no, lying when Sheldon asks Linkletter if he is using Sheldon to get closer to his Meemaw. All and all, he's a real piece of shit.
- Grease Monkey: Works as a mechanic and puts Georgie on the path to becoming Dr. Tire.
- Henpecked Husband: Constantly yelled at and bossed around by Brenda. He and George both bond over how they are often dominated by their wives.
- Nice Guy: Unlike his wife, he's always courteous to the Coopers.
- Odd Name Out: The only member of the Sparks family whose first name doesn't begin with the letter "B".
The wife of Herschel Sparks and the mother of Billy and Bobbi Sparks. She works at the bowling alley that Connie goes to.
- Hate Sink: She's a straight bitch without a single redeeming quality who likes to antagonize the Cooper family.
- She calls both Sheldon and Missy "weird". This is coming from the mother of Billy Sparks.
- She tells Mary that Missy playing baseball isn't ladylike, then immediately yells at Billy "like a dock foreman" (in Mary's words.)
- Jerkass: She treats everyone terribly, even her own husband and children.
- Not So Different: "A Party Invitation, Football Grapes and an Earth Chicken" has Brenda and Mary acknowledge that they both have difficulty dealing with children that are considered strange and unpopular, Mary with Sheldon, and Brenda with Billy.
A policewoman in Medford who becomes romantically involved with Pastor Jeff after his divorce.
A baseball coach who lets Missy join his group and he also begins dating Meemaw after her breakup with Dr. Sturgis. He also owns a sporting goods store and hires Georgie as a salesman.
- Derailing Love Interests: While it may be too soon to say, the way he treats Dr. Sturgis in the latter portion of season 3 seems to signal that he's headed in this direction. But he's shown some jerkass qualities ever since he showed up.
- Everyone Has Standards: As much as he belittles John on their fishing trip, he stops himself from mentioning John's mental problems.
- Jerkass Has a Point: While the way Dale treats John is unacceptable, his reasons for doing so are at least understandable, as John spied on him after he found out Connie was dating Dale.
- Jerk Jock: He's a baseball coach and definitely has a bad side to him.
- Jerk with a Heart of Gold: Despite first appearing to be a sexist pig for not allowing Missy to try out for baseball, he soon reveals himself to be quite a stand-up guy and does coach her well once he finally puts her on the team. Though he is quite a jerk to Dr. Sturgis and his bad qualities are slowly revealing themselves, hinting that he may well be a Jerk with a Heart of Jerk.
- Nice Guy: He is a nice man and respectful to everyone. Aside from Dr. Strugis
- Not So Different: He has been married once and had at least one child and a grandson while Meemaw has had 3 children and 3 grandchildren. But while Dale is divorced from his wife, Meemaw is widowed since her husband died.
- Straw Misogynist: Subverted. He has reservations about Missy trying out for baseball, mainly because he doesn't want the boys to hurt her instead of believing that girls shouldn't play sports. His fears quickly subside once he sees Missy beat the crap out of a pitcher on the opposing team for nearly beaning her in the face several times.