Amazon-Video Comedy Central Showtime Apple TV+ DC Universe Disney Plus YouTube Premium HBO Max Peacock Netflix Vudu HBO Go Hulu Plus Amazon Prime CBS All Access Verizon

Join or Sign In

Sign in to customize your TV listings

Continue with Facebook Continue with email

By joining TV Guide, you agree to our Terms of Use and acknowledge the data practices in our Privacy Policy.

The Big Bang Theory Season 4 Episodes

24 Episodes 2010 - 2011

In Season 4 of the sitcom, Sheldon (Jim Parsons) begins an unorthodox relationship with an equally brilliant—and equally awkward—neuroscientist named Amy Farrah Fowler (Mayim Bialik, who is bumped from recurring cast member to series regular by the end of the season). Meanwhile, Leonard (Johnny Galecki) starts dating a new woman, but there's only one problem: She's Raj's (Kunal Nayyar) sister, and he's not too happy about it. Kaley Cuoco and Simon Helberg also star.

Episode 1

The Robotic Manipulation

Thu, Sep 23, 2010 30 mins

In the fourth-season opener, Sheldon goes on a date with Amy Fowler, his first date ever, and Penny finds herself accompanying them.

Where to Watch
The Big Bang Theory, Season 4 Episode 1 image

Episode 2

The Cruciferous Vegetable Amplification

Thu, Sep 30, 2010 30 mins

Sheldon hatches a plan to extend his lifespan when he realises he won't be around to see the technology that will be able to download his consciousness into a robot.

Where to Watch
The Big Bang Theory, Season 4 Episode 2 image

Episode 3

The Zazzy Substitution

Thu, Oct 7, 2010 30 mins

Everyone worries for Sheldon, who begins searching for non-human companionship.

Where to Watch
The Big Bang Theory, Season 4 Episode 3 image

Episode 4

The Hot Troll Deviation

Thu, Oct 14, 2010 30 mins

Wolowitz is embarrassed when a secret of his is revealed; and Sheldon and Raj battle at work.

Where to Watch
The Big Bang Theory, Season 4 Episode 4 image

Episode 5

The Desperation Emanation

Thu, Oct 21, 2010 30 mins

Sheldon meets Amy's mother and comes to the realisation that he no longer wants to see Amy; and Leonard realises that everyone is in a relationship except for him.

Where to Watch
The Big Bang Theory, Season 4 Episode 5 image

Episode 6

The Irish Pub Formulation

Thu, Oct 28, 2010 30 mins

Raj's sister visits and inadvertently causes trouble for the friends.

Where to Watch
The Big Bang Theory, Season 4 Episode 6 image

Episode 7

The Apology Insufficiency

Thu, Nov 4, 2010 30 mins

Howard baffles Sheldon when he won't accept his apology; and an FBI agent interviews the guys for Howard's security clearance.

Where to Watch
The Big Bang Theory, Season 4 Episode 7 image

Episode 8

The 21-Second Excitation

Thu, Nov 11, 2010 30 mins

The guys camp out in a line hoping to see an anticipated movie, while Penny and Bernadette arrange Amy's first slumber party.

Where to Watch
The Big Bang Theory, Season 4 Episode 8 image

Episode 9

The Boyfriend Complexity

Thu, Nov 18, 2010 30 mins

Penny asks Leonard to lie to her visiting father, while Howard, Raj and Bernadette spend all night looking through a telescope.

Where to Watch
The Big Bang Theory, Season 4 Episode 9 image

Episode 10

The Alien Parasite Hypothesis

Thu, Dec 9, 2010 30 mins

Amy is attracted to Penny's ex-boyfriend; and Raj and Howard argue about which of them would be a better superhero.

Where to Watch
The Big Bang Theory, Season 4 Episode 10 image

Episode 11

The Justice League Recombination

Thu, Dec 16, 2010 30 mins

The guys borrow Penny's new boyfriend when they enter a costume contest as members of the Justice League.

Where to Watch
The Big Bang Theory, Season 4 Episode 11 image

Episode 12

The Bus Pants Utilization

Thu, Jan 6, 2011 30 mins

Leonard has a great idea for a smartphone app, and it causes friction with Sheldon.

Where to Watch
The Big Bang Theory, Season 4 Episode 12 image

Episode 13

The Love Car Displacement

Thu, Jan 20, 2011 30 mins

Howard is jealous when Bernadette runs into her old boyfriend at a science event they're attending.

Where to Watch
The Big Bang Theory, Season 4 Episode 13 image

Episode 14

The Thespian Catalyst

Thu, Feb 3, 2011 30 mins

Sheldon wants acting lessons from Penny, hoping they will make him a better teacher.

Where to Watch
The Big Bang Theory, Season 4 Episode 14 image

Episode 15

The Benefactor Factor

Thu, Feb 10, 2011 30 mins

Leonard has a moral crisis when he meets a wealthy widow who is willing to help the university.

Where to Watch
The Big Bang Theory, Season 4 Episode 15 image

Episode 16

The Cohabitation Formulation

Thu, Feb 17, 2011 30 mins

Howard contemplates a serious decision in his relationship with Bernadette; and Leonard and Raj's sister start seeing each other again.

Where to Watch
The Big Bang Theory, Season 4 Episode 16 image

Episode 17

The Toast Derivation

Thu, Feb 24, 2011 30 mins

Sheldon is in crisis when he realizes he's not the epicenter of the group, so, he decides to find new friends.

Where to Watch
The Big Bang Theory, Season 4 Episode 17 image

Episode 18

The Prestidigitation Approximation

Thu, Mar 10, 2011 30 mins

Leonard has a tough choice to make when Priya asks him to stop spending time with Penny, forcing him to choose between the two women; and Howard keeps pestering Sheldon with a magic trick.

Where to Watch
The Big Bang Theory, Season 4 Episode 18 image

Episode 19

The Zarnecki Incursion

Thu, Mar 31, 2011 30 mins

The guys become sleuths to find out who hacked Sheldon's online-game account.

Where to Watch
The Big Bang Theory, Season 4 Episode 19 image

Episode 20

The Herb Garden Germination

Thu, Apr 7, 2011 30 mins

Sheldon and Amy spread gossip as part of an experiment; and Howard and Bernadette's relationship gets serious. Physicist Brian Greene has a cameo.

Where to Watch
The Big Bang Theory, Season 4 Episode 20 image

Episode 21

The Agreement Dissection

Thu, Apr 28, 2011 30 mins

Priya uses her legal expertise to rip apart Sheldon's roommate agreement, and the women take the flustered Sheldon out dancing.

Where to Watch
The Big Bang Theory, Season 4 Episode 21 image

Episode 22

The Wildebeest Implementation

Fri, Mar 25, 2011 30 mins

Raj makes an attempt to cure his phobia of talking to women; and Penny spies on Leonard and Priya with the help of Bernadette.

Where to Watch
The Big Bang Theory, Season 4 Episode 22 image

Episode 23

The Engagement Reaction

Thu, May 12, 2011 30 mins

Howard finally tells his mother that he's marrying Bernadette, and the news puts her in the hospital.

Where to Watch
The Big Bang Theory, Season 4 Episode 23 image

Episode 24

The Roommate Transmogrification

Thu, May 19, 2011 30 mins

In the fourth-season finale, Raj moves in with Sheldon when Leonard and Priya's "Star Trek" bedroom fantasy is too much for him; and the guys tease Howard when Bernadette gets her PhD, making Howard the only one without a doctorate.

Where to Watch
The Big Bang Theory, Season 4 Episode 24 image