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The Best Episodes of The Big Bang Theory Season 5

Every episode of The Big Bang Theory Season 5 ranked from best to worst. Discover the Best Episodes of The Big Bang Theory Season 5!

Binge this in 8h 13m•Peaking at 8.5/10

Physicists Leonard and Sheldon find their nerd-centric social circle with pals Howard and Raj expanding when aspiring actress Penny moves in next door.

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Episode Rankings

  1. #1 Fan Favorite
    The Big Bang Theory Season 5 Episode 1 - The Skank Reflex Analysis
    8.0/10(4875 votes)

    #1 - The Skank Reflex Analysis

    S5:E1

    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.

    Director:Mark Cendrowski
    Writer:Unknown

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  2. The Big Bang Theory Season 5 Episode 2 - The Infestation Hypothesis
    8.0/10(4380 votes)

    #2 - The Infestation Hypothesis

    S5:E2

    A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

    Director:Mark Cendrowski
    Writer:Unknown

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  3. The Big Bang Theory Season 5 Episode 3 - The Pulled Groin Extrapolation
    7.6/10(4203 votes)

    #3 - The Pulled Groin Extrapolation

    S5:E3

    Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.

    Director:Mark Cendrowski
    Writer:Unknown

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  4. The Big Bang Theory Season 5 Episode 4 - The Wiggly Finger Catalyst
    7.8/10(4272 votes)

    #4 - The Wiggly Finger Catalyst

    S5:E4

    Penny plays Matchmaker for Raj, which results in him finding a girl he is comfortable talking to.

    Director:Mark Cendrowski
    Writer:Unknown

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  5. The Big Bang Theory Season 5 Episode 5 - The Russian Rocket Reaction
    8.0/10(4228 votes)

    #5 - The Russian Rocket Reaction

    S5:E5

    Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.

    Director:Mark Cendrowski
    Writer:Unknown

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  6. The Big Bang Theory Season 5 Episode 6 - The Rhinitis Revelation
    7.5/10(4164 votes)

    #6 - The Rhinitis Revelation

    S5:E6

    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.

    Director:Howard Murray
    Writer:Unknown

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  7. The Big Bang Theory Season 5 Episode 7 - The Good Guy Fluctuation
    8.5/10(5013 votes)

    #7 - The Good Guy Fluctuation

    S5:E7

    A cute comic book artist puts Leonard and Priya’s relationship to the test, while Sheldon tries to scare the guys for Halloween.

    Director:Mark Cendrowski
    Writer:Unknown

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  8. The Big Bang Theory Season 5 Episode 8 - The Isolation Permutation
    7.6/10(4125 votes)

    #8 - The Isolation Permutation

    S5:E8

    Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.

    Director:Mark Cendrowski
    Writer:Unknown

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  9. The Big Bang Theory Season 5 Episode 9 - The Ornithophobia Diffusion
    8.1/10(4342 votes)

    #9 - The Ornithophobia Diffusion

    S5:E9

    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 Bernadette and Amy to overcome his fear of birds.

    Director:Mark Cendrowski
    Writer:Unknown

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  10. The Big Bang Theory Season 5 Episode 10 - The Flaming Spittoon Acquisition
    7.9/10(4182 votes)

    #10 - The Flaming Spittoon Acquisition

    S5:E10

    When Stuart asks Amy out on a date, Sheldon must confront his feelings and consider where his relationship with Amy is going.

    Director:Mark Cendrowski
    Writer:Unknown

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  11. The Big Bang Theory Season 5 Episode 11 - The Speckerman Recurrence
    7.3/10(4154 votes)

    #11 - The Speckerman Recurrence

    S5:E11

    Leonard must face his fears after being contacted by his high school tormentor.

    Director:Anthony Rich
    Writer:Unknown

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  12. The Big Bang Theory Season 5 Episode 12 - The Shiny Trinket Maneuver
    7.6/10(4147 votes)

    #12 - The Shiny Trinket Maneuver

    S5:E12

    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.

    Director:Mark Cendrowski
    Writer:Unknown

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  13. The Big Bang Theory Season 5 Episode 13 - The Recombination Hypothesis
    8.1/10(4391 votes)

    #13 - The Recombination Hypothesis

    S5:E13

    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.

    Director:Mark Cendrowski
    Writer:Unknown

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  14. The Big Bang Theory Season 5 Episode 14 - The Beta Test Initiation
    8.2/10(4379 votes)

    #14 - The Beta Test Initiation

    S5:E14

    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. Meanwhile, Sheldon decides to start a YouTube series entitled "Sheldon Cooper presents Fun with Flags" with the help of Amy.

    Director:Mark Cendrowski
    Writer:Unknown

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  15. The Big Bang Theory Season 5 Episode 15 - The Friendship Contraction
    7.7/10(4013 votes)

    #15 - The Friendship Contraction

    S5:E15

    Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.

    Director:Mark Cendrowski
    Writer:Unknown

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  16. The Big Bang Theory Season 5 Episode 16 - The Vacation Solution
    7.5/10(3993 votes)

    #16 - The Vacation Solution

    S5:E16

    When Sheldon is forced to take his vacation, he goes to work with Amy in her neurobiology lab.

    Director:Mark Cendrowski
    Writer:Unknown

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  17. The Big Bang Theory Season 5 Episode 17 - The Rothman Disintegration
    7.7/10(4098 votes)

    #17 - The Rothman Disintegration

    S5:E17

    Sheldon battles Kripke for a coveted office at the university. Penny receives a very unusual gift from Amy.

    Director:Mark Cendrowski
    Writer:Unknown

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  18. The Big Bang Theory Season 5 Episode 18 - The Werewolf Transformation
    8.2/10(4307 votes)

    #18 - The Werewolf Transformation

    S5:E18

    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 she plays.

    Director:Mark Cendrowski
    Writer:Unknown

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  19. The Big Bang Theory Season 5 Episode 19 - The Weekend Vortex
    8.1/10(4114 votes)

    #19 - The Weekend Vortex

    S5:E19

    Sheldon must choose between joining Amy at her aunt's birthday party or playing videogames all weekend with the guys.

    Director:Mark Cendrowski
    Writer:Unknown

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  20. The Big Bang Theory Season 5 Episode 20 - The Transporter Malfunction
    8.1/10(4253 votes)

    #20 - The Transporter Malfunction

    S5:E20

    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” after his parents set him up on a date.

    Director:Mark Cendrowski
    Writer:Unknown

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  21. The Big Bang Theory Season 5 Episode 21 - The Hawking Excitation
    8.5/10(4701 votes)

    #21 - The Hawking Excitation

    S5:E21

    When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

    Director:Mark Cendrowski
    Writer:Unknown

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  22. The Big Bang Theory Season 5 Episode 22 - The Stag Convergence
    7.7/10(4070 votes)

    #22 - The Stag Convergence

    S5:E22

    After the guys throw Howard a bachelor party, Bernadette reconsiders marrying him after learning about his sexual history.

    Director:Peter Chakos
    Writer:Unknown

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  23. The Big Bang Theory Season 5 Episode 23 - The Launch Acceleration
    8.1/10(4029 votes)

    #23 - The Launch Acceleration

    S5:E23

    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 in the bedroom.

    Director:Mark Cendrowski
    Writer:Unknown

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  24. The Big Bang Theory Season 5 Episode 24 - The Countdown Reflection
    8.5/10(4563 votes)

    #24 - The Countdown Reflection

    S5:E24

    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 astronaut Mike Massimino has a cameo as himself.

    Director:Mark Cendrowski
    Writer:Unknown

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Season 5 Ratings Summary

"The Skank Reflex Analysis" is the best rated episode of "The Big Bang Theory" season 5. It scored 8/10 based on 4875 votes. Directed by Mark Cendrowski and written by Unknown, it aired on 9/22/2011. This episode is rated 0.0 points higher than the second-best, "The Infestation Hypothesis".