The BEST episodes of The Big Bang Theory season 4

Every episode of The Big Bang Theory season 4, ranked from best to worst by thousands of votes from fans of the show. The best episodes of The Big Bang Theory season 4!

A woman who moves into an apartment across the hall from two brilliant but socially awkward physicists shows them how little they know about life outside of the laboratory.

Last Updated: 3/26/2024Network: CBSStatus: Ended
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The Roommate Transmogrification
star
8.05
13507 votes

#1 - The Roommate Transmogrification

Season 4 - Episode 24 - Aired 5/19/2011

When Bernadette receives her PhD, Wolowitz feels emasculated. Raj and Leonard swap apartments and Penny does something she regrets.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Prestidigitation Approximation
star
7.95
12979 votes

#2 - The Prestidigitation Approximation

Season 4 - Episode 18 - Aired 3/10/2011

Sheldon is baffled by Wolowitz's magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Herb Garden Germination
star
7.95
13082 votes

#3 - The Herb Garden Germination

Season 4 - Episode 20 - Aired 4/7/2011

Sheldon and Amy decide to start several rumors about the others as a test. Meanwhile, Howard takes his relationship with Bernadette to an even higher level.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Justice League Recombination
star
7.94
14439 votes

#4 - The Justice League Recombination

Season 4 - Episode 11 - Aired 12/16/2010

The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Boyfriend Complexity
star
7.94
14710 votes

#5 - The Boyfriend Complexity

Season 4 - Episode 9 - Aired 11/18/2010

Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Engagement Reaction
star
7.85
13183 votes

#6 - The Engagement Reaction

Season 4 - Episode 23 - Aired 5/12/2011

When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.

Directors: Howard Murray
Watch Now:AmazonApple TV
The Agreement Dissection
star
7.85
13814 votes

#7 - The Agreement Dissection

Season 4 - Episode 21 - Aired 4/28/2011

When Priya finds a loophole in the roommate agreement to throw Sheldon out for the night, Penny, Amy and Bernadette take him to a nightclub.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Robotic Manipulation
star
7.85
15586 votes

#8 - The Robotic Manipulation

Season 4 - Episode 1 - Aired 9/23/2010

Penny tags along on Sheldon's first ever date; Wolowitz finds a new use for a robotic arm.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Love Car Displacement
star
7.85
13486 votes

#9 - The Love Car Displacement

Season 4 - Episode 13 - Aired 1/20/2011

When the gang road trips to a conference, tensions run high when Bernadette runs into her ex-boyfriend.

Directors: Anthony Rich
Watch Now:AmazonApple TV
The Zarnecki Incursion
star
7.85
13625 votes

#10 - The Zarnecki Incursion

Season 4 - Episode 19 - Aired 3/31/2011

The guys go all out to help Sheldon find the person responsible for hacking his online gaming account, while the girls' hatred for Priya increases.

Directors: Peter Chakos
Watch Now:AmazonApple TV
The Toast Derivation
star
7.83
13208 votes

#11 - The Toast Derivation

Season 4 - Episode 17 - Aired 2/24/2011

Sheldon becomes concerned when everybody begins to hang out at Raj's apartment and discovers Leonard is the center of the group.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Cruciferous Vegetable Amplification
star
7.83
15719 votes

#12 - The Cruciferous Vegetable Amplification

Season 4 - Episode 2 - Aired 9/30/2010

Realizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Benefactor Factor
star
7.83
13635 votes

#13 - The Benefactor Factor

Season 4 - Episode 15 - Aired 2/10/2011

A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The 21-Second Excitation
star
7.83
14084 votes

#14 - The 21-Second Excitation

Season 4 - Episode 8 - Aired 11/11/2010

While the guys camp in line for a long-awaited movie screening, Penny and Bernadette invite Amy to her first slumber party.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Cohabitation Formulation
star
7.83
13432 votes

#15 - The Cohabitation Formulation

Season 4 - Episode 16 - Aired 2/17/2011

As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj's sister Priya.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Irish Pub Formulation
star
7.82
14484 votes

#16 - The Irish Pub Formulation

Season 4 - Episode 6 - Aired 10/28/2010

Leonard keeps a romantic affair a secret from Sheldon, Howard and Raj.

Directors: Mark Cendrowski
Watch Now:AmazonApple TV
The Wildebeest Implementation
star
7.75
13189 votes

#17 - The Wildebeest Implementation

Season 4 - Episode 22 - Aired 5/5/2011

Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Apology Insufficiency
star
7.74
13904 votes

#18 - The Apology Insufficiency

Season 4 - Episode 7 - Aired 11/4/2010

Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Zazzy Substitution
star
7.67
14759 votes

#19 - The Zazzy Substitution

Season 4 - Episode 3 - Aired 10/7/2010

The guys are concerned as Sheldon searches for an alternative to human companionship.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Hot Troll Deviation
star
7.66
14537 votes

#20 - The Hot Troll Deviation

Season 4 - Episode 4 - Aired 10/14/2010

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Desperation Emanation
star
7.65
14571 votes

#21 - The Desperation Emanation

Season 4 - Episode 5 - Aired 10/21/2010

Leonard realizes he’s the only one without a girlfriend, while Sheldon wants to get rid of his.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Thespian Catalyst
star
7.64
13811 votes

#22 - The Thespian Catalyst

Season 4 - Episode 14 - Aired 2/3/2011

Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friend's girlfriend.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Alien Parasite Hypothesis
star
7.64
14496 votes

#23 - The Alien Parasite Hypothesis

Season 4 - Episode 10 - Aired 12/9/2010

Amy finds she has sexual feelings for Penny's ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.

Directors: Mark Cendrowski
Watch Now:Apple TV
The Bus Pants Utilization
star
7.64
13817 votes

#24 - The Bus Pants Utilization

Season 4 - Episode 12 - Aired 1/6/2011

Leonard's idea for a smartphone app derails his friendship with Sheldon.

Directors: Mark Cendrowski
Watch Now:Apple TV