Penny is a fictional character on the CBS television series The Big Bang Theory, portrayed by American actress Kaley Cuoco.
Penny is the primary female character on the show, befriending her across-the-hall neighbors Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons), two physicists who work at the nearby Caltech University. Penny's lack of advanced education and outgoing personality drastically contrast the personalities of the primary male characters in the series, even though she is considered part of their group. She also is the love interest of Leonard, whom she dates during the third and fifth seasons.
Originally from Omaha, Nebraska, Penny is a waitress at the local Cheesecake Factory with aspirations of becoming an actress. She is a Sagittarius, meaning she was born between November 22 and December 21. She has full confidence in horoscopes and often has arguments with Sheldon and Leonard about their accuracy.
In contrast to the rest of the group, Penny is not well-educated (though she is smart) or savvy in a specific technical field, but she has great social skills and is very knowledgeable about pop culture. She is also messy and disorganized, but appears to like it that way.
While usually very kind, Penny has a bad temper which has erupted on many occasions, such as when Sheldon broke into her apartment to clean, when she confronted Howard over his "creepy" flirting, or when Sheldon "banished" her from their social group. Leonard has likened her to The Hulk when she gets angry, while Sheldon once said to his friend Stuart that she would "maul [him] like a rabid Wolverine" if Stuart woke her up.
Penny is a terrible driver (she ignores speed bumps, drives too fast, fails to service her vehicle regularly, and has left her car's passenger side wing mirror "in a parking lot in Hollywood"). She also has a Chinese character tattooed on her right buttock, which, according to her, means "courage" (Chinese: 勇) but is revealed to mean "soup" (traditional Chinese: 湯) by Sheldon. She uses vanilla oil as perfume and snores loudly (especially when on her back). Early in the series, she claimed to be vegetarian, with the exception of fish and the "occasional steak...I love steak!".
For the most part, Penny cannot stand Leonard's roommate Sheldon Cooper, and the two of them have clashed several times. Actor Jim Parsons, who portrays Sheldon, described the characters as "polar opposites".
In one episode, Sheldon tries to "improve" Penny using chocolate, rewarding her for what he considers to be "correct behavior", as in operant conditioning with lab rats. As Sheldon observed, Penny will often call someone "sweetie" coupled with a thinly-veiled insult.
Despite this, at times Penny and Sheldon have shown to be good friends; Penny took care of Sheldon while he was ill and let him stay at her apartment when he was locked out of his; Sheldon lent money to Penny when she needed it and took care of her when she dislocated her shoulder. During a Christmas episode, Penny gave Sheldon a signed napkin used by Leonard Nimoy. In return, Sheldon gave Penny multiple baskets of bath products and then a long hug, to both her and Leonard's surprise. When Sheldon's World of Warcraft account was hacked and the four guys all backed down from the much larger hacker, Penny kicked the hacker in the testicles.
Although Penny's personality usually contrasts to that of her nerdy friends, in the later episodes Penny has shown some of her own geekiness too, either intentionally or unintentionally.
Penny was surprisingly good the first time she played Halo 3, camping at Sheldon's spawn location and killing him before he could move, which greatly aggravated him.
In one instance, Penny was critical of the guys' interests in toys and collectibles, but Sheldon retorted by noting her collection of stuffed bears and other such childish things (Hello Kitty, Beanie Babies, My Little Pony, etc.).
After Sheldon introduces her to the theory of Schrödinger's cat during the build up to her and Leonard's date as the climax to season 1, Penny attempts to reuse the metaphor with a new boyfriend in "The Codpiece Topology".
After a brief introduction to the game Age of Conan by Sheldon, Penny creates a character named Queen Penelope. Penny became addicted, to the point of ignoring her friends and calling Sheldon at all hours of the day for advice. She finally overcame her addiction when she realized she had agreed to go on a virtual "date" within the game with Howard.
After Alicia, a new tenant in the building, stole the boys' attention from her, Penny became jealous and tried to win over the boys again by making a physicist joke. To her own surprise, she even makes a casual reference to Star Trek while engaged in idle conversation, an indication of her growing geek awareness.
In "The Electric Can Opener Fluctuation", when attempting to console Sheldon (and failing miserably), she mentions events that occurred in the new Star Trek movie.
In "The Wheaton Recurrence," Penny quoted, "Do, or do not. There is no try" while in bed with Leonard, and even mentioned she knew it was from The Empire Strikes Back. Leonard was pleasantly shocked that he was "in bed with a beautiful woman who can quote Yoda," and for the first time told Penny that he loved her, which then led to their breakup.
In "The Apology Insufficiency," Penny had a chat with Sheldon and displayed knowledge of the Kobayashi Maru test, a plot device in Star Trek, impressing him.
In "The Love Car Displacement", Penny ends up sharing Leonard's bed and she tells him that as far as romantic activities go, below her waist, her shields are up alluding to the Star Trek defensive system.
In "The Werewolf Transformation", Penny beats Leonard at chess despite she still does not know how different pieces are called. Leonard later admitted that Penny played chess like "Bobby Fischer"
In "The Adhesive Duck Deficiency" when Sheldon is driving her to the hospital she says: Warp speed ahead, Mr. Spock. Sheldon objects that Mr. spock would never pilot the Enterprise.