The Big Bang Theory: Season 5
The Big Bang Theory Season 5 continues the overarching saga across 24 episodes.
Season 5 Lore Primer
Key plot threads, lore context, and character stakes you need to remember before diving into this season.
- Picks up essential narrative continuity directly following the events of The Big Bang Theory Season 4.
- Character alliances, factions, and personal loyalties undergo significant shifts under escalating stakes.
- Addresses unresolved cliffhangers and thematic mysteries introduced during previous seasons.
- Establishes the primary seasonal conflict that drives serialized character arcs toward the finale.
Season overview
The Big Bang Theory Season 5 continues the overarching saga across 24 episodes.
Episode Guide
Season 5 Progress Shield
The Skank Reflex Analysis
Sep 22, 2011
Penny is worried with how damaged her friendship with the guys will be in the aftermath of her sleeping with Raj while Sheldon becomes the leader of the paintball team.
The Infestation Hypothesis
Sep 22, 2011
A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.
The Pulled Groin Extrapolation
Sep 29, 2011
Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.
The Wiggly Finger Catalyst
Oct 6, 2011
Penny plays Matchmaker for Raj, which results in him finding a girl he is comfortable talking to.
The Russian Rocket Reaction
Oct 13, 2011
Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.
The Rhinitis Revelation
Oct 20, 2011
Sheldon's mother, Mary Cooper, comes to visit, but Sheldon is annoyed that she also spends time with the rest of the gang, instead of catering to his every demand.
The Good Guy Fluctuation
Oct 27, 2011
A cute comic book artist puts Leonard and Priya’s relationship to the test, while Sheldon tries to scare the guys for Halloween.
The Isolation Permutation
Nov 3, 2011
Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.
The Ornithophobia Diffusion
Nov 10, 2011
Leonard and Penny try hanging out as friends on a 'non-date', but end up purposely ruining each others chances with perspective dates. Meanwhile, Sheldon enlists the help of Bernad
The Flaming Spittoon Acquisition
Nov 17, 2011
When Stuart asks Amy out on a date, Sheldon must confront his feelings and consider where his relationship with Amy is going.
The Speckerman Recurrence
Dec 8, 2011
Leonard must face his fears after being contacted by his high school tormentor.
The Shiny Trinket Maneuver
Jan 12, 2012
Sheldon gets in trouble with Amy when he isn't impressed by her recent accomplishment, and Howard must come to grips with Bernadette's dislike of children.
The Recombination Hypothesis
Jan 19, 2012
Leonard, who broke up with Priya, asks Penny out to a spur-of the-moment romantic dinner for two, and the duo contemplates on their relationship.
The Beta Test Initiation
Jan 26, 2012
Leonard and Penny deal with the idea of starting a relationship again and Raj finally finds a "woman" he can talk to without being drunk, in the form of Siri on his new phone. Mean
The Friendship Contraction
Feb 2, 2012
Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.
The Vacation Solution
Feb 9, 2012
When Sheldon is forced to take his vacation, he goes to work with Amy in her neurobiology lab.
The Rothman Disintegration
Feb 16, 2012
Sheldon battles Kripke for a coveted office at the university. Penny receives a very unusual gift from Amy.
The Werewolf Transformation
Feb 23, 2012
Sheldon becomes agitated when his regular barber is out sick. Astronaut training causes Howard to reconsider wanting to go into space. Penny beats Leonard in chess, the first time
The Weekend Vortex
Mar 8, 2012
Sheldon must choose between joining Amy at her aunt's birthday party or playing videogames all weekend with the guys.
The Transporter Malfunction
Mar 29, 2012
Penny buys Leonard and Sheldon “Star Trek” collectibles as a thank-you, leading Sheldon to be haunted by Mr. Spock. Meanwhile, Raj decides he has met the “Future Mrs. Koothrappali”
The Hawking Excitation
Apr 5, 2012
When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.
The Stag Convergence
Apr 26, 2012
After the guys throw Howard a bachelor party, Bernadette reconsiders marrying him after learning about his sexual history.
The Launch Acceleration
May 3, 2012
When NASA moves up Howard's mission, he must face his fears and Bernadette's dad, thus putting the wedding plans in jeopardy. Meanwhile, Leonard says something surprising to Penny
The Countdown Reflection
May 10, 2012
The fifth season ends with Howard and Bernadette deciding to get married before his NASA mission, causing the gang to scurry into overdrive in an effort to stage the wedding. NASA