The Big Bang Theory

Season 4

TV-PG
80%91%
This season the Big Bang gang’s romantic universe expands. On the rebound from Penny, Leonard falls into the arms of Raj’s sister Priya. Sheldon gets a girlfriend, or rather a friend who is a girl: Amy, a dour neurobiologist who declares herself besties with Penny. Howard and Bernadette heat up. And so do Raj and Bernadette (at least in Raj’s Bollywood daydream).
Where to Watch Season 4
24 Episodes
  • The Robotic Manipulation
    E1
    Episode 1The Robotic ManipulationPenny tags along on Sheldon's first ever date; Wolowitz finds a new use for a robotic arm.
  • The Cruciferous Vegetable Amplification
    E2
    Episode 2The Cruciferous Vegetable AmplificationRealizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.
  • The Zazzy Substitution
    E3
    Episode 3The Zazzy SubstitutionThe guys are concerned as Sheldon searches for an alternative to human companionship.
  • The Hot Troll Deviation
    E4
    Episode 4The Hot Troll DeviationAn embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.
  • The Desperation Emanation
    E5
    Episode 5The Desperation EmanationSheldon is scared that he is in a relationship when Amy asks him to meet her mother, and Leonard asks Howard and Bernadette to set him up because he is the only person in the group without a girlfriend.
  • The Irish Pub Formulation
    E6
    Episode 6The Irish Pub FormulationLeonard keeps an affair a secret from Sheldon, Howard and Raj.
  • The Apology Insufficiency
    E7
    Episode 7The Apology InsufficiencySheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.
  • The 21-Second Excitation
    E8
    Episode 8The 21-Second ExcitationWhile the guys camp in line for a long-awaited movie screening, Penny and Bernadette invite Amy to her first slumber party.
  • The Boyfriend Complexity
    E9
    Episode 9The Boyfriend ComplexityPenny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.
  • The Alien Parasite Hypothesis
    E10
    Episode 10The Alien Parasite HypothesisAmy finds she has sexual feelings for Penny's ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.
  • The Justice League Recombination
    E11
    Episode 11The Justice League RecombinationThe guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.
  • The Bus Pants Utilization
    E12
    Episode 12The Bus Pants UtilizationLeonard's idea for a smartphone app derails his friendship with Sheldon.
  • The Love Car Displacement
    E13
    Episode 13The Love Car DisplacementBernadette runs into her ex-boyfriend while attending a science event with Wolowitz.
  • The Thespian Catalyst
    E14
    Episode 14The Thespian CatalystHoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friend's girlfriend.
  • The Benefactor Factor
    E15
    Episode 15The Benefactor FactorA wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.
  • The Cohabitation Formulation
    E16
    Episode 16The Cohabitation FormulationAs Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj's sister.
  • The Toast Derivation
    E17
    Episode 17The Toast DerivationSheldon becomes concerned when everybody begins to hang out at Raj's apartment and discovers Leonard is the center of the group.
  • The Prestidigitation Approximation
    E18
    Episode 18The Prestidigitation ApproximationSheldon is baffled by Wolowitz's magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.
  • The Zarnecki Incursion
    E19
    Episode 19The Zarnecki IncursionSheldon's online-game account is hacked by Todd Zarnecki, who then proceeds to steal all his items prompting the guys to go on a quest to retrieve them. Penny, Bernadette and Amy discuss how Penny groomed Leonard to be willing to try various things and more adventurous boyfriend... for some other woman — Priya.
  • The Herb Garden Germination
    E20
    Episode 20The Herb Garden GerminationSheldon and Amy decide to start several rumors about the others as a test. Meanwhile, Howard takes his relationship with Bernadette to even higher level.
  • The Agreement Dissection
    E21
    Episode 21The Agreement DissectionWhen Leonard spends too much time in the shower with Priya, Sheldon charges Leonard with two violations of the roommate agreement. However, before he can get too far, Priya uses her skills as a lawyer to nullify the charges due to the agreement's vague wording, much to Sheldon's dismay. When the guys take advantage of Priya's skills in order to eat Greek food on pizza night, Sheldon goes to Penny, who invites him to a girls' night out with Amy and Bernadette, which Sheldon agrees to after Penny mentions that they may be talking trash about Priya. After the girls drink some cocktails, they decide to take Sheldon dancing, which Sheldon reluctantly goes along with. After dancing, Sheldon takes an intoxicated Amy back to her apartment and as well as talking about Priya, meets a monkey who is addicted to smoking cigarettes. Amy tells Sheldon not to give in to Priya's law skills, before kissing him and going to her bathroom to vomit.
  • The Wildebeest Implementation
    E22
    Episode 22The Wildebeest ImplementationRaj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.
  • The Engagement Reaction
    E23
    Episode 23The Engagement ReactionWhen Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.
  • The Roommate Transmogrification
    E24
    Episode 24The Roommate TransmogrificationWhen Bernadette receives her PhD, Wolowitz feels emasculated. Raj and Leonard swap places and Penny does something she's regrets.
Cast of Season 4
  • Johnny GaleckiLeonard Hofstadter
  • Jim ParsonsSheldon Cooper
  • Kaley CuocoPenny
  • Simon HelbergHoward Wolowitz
  • Kunal NayyarRajesh Koothrappali
  • Melissa RauchBernadette Rostenkowski
  • Mayim BialikAmy Farrah Fowler
Season 4 Reviews
Watch Season 4 Videos
  • The Big Bang Theory: Season 4
    The Big Bang Theory: Season 4Trailer
  • The Big Bang Theory: Penny
    The Big Bang Theory: PennyBehind the Scenes
  • The Big Bang Theory: Behind The Scenes
    The Big Bang Theory: Behind The ScenesBehind the Scenes
  • The Big Bang Theory: The Boyfriend Complexity
    The Big Bang Theory: The Boyfriend ComplexityScene
 
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