![The Big Bang Theory](https://tv-fanatic-res.cloudinary.com/iu/s--iQdBt3rU--/c_fill,h_315,w_851/d_tv-fanatic-placeholder-square.png,f_auto,fl_lossy,q_75/v1421782016/banner/the-big-bang-theory.jpg)
The Big Bang Theory
Thursdays 8:00 PM on CBSWatch The Big Bang Theory Season 4 Online
Watch The Big Bang Theory Season 4 full episodes online, free and paid options via our partners and affiliates.
![New Roomies](https://tv-fanatic-res.cloudinary.com/iu/s--C8owkf_k--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371220295/new-roomies.png)
Raj moves in with Sheldon on the fourth season finale of The Big Bang Theory. This takes Penny by surprise.
![Kunal Nayyar Promo Pic](https://tv-fanatic-res.cloudinary.com/iu/s--WKKZPoHh--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371218365/kunal-nayyar-promo-pic.png)
When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.
![Raj in Action](https://tv-fanatic-res.cloudinary.com/iu/s--AJRIEnLO--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371220032/raj-in-action.png)
Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.
![Sheldon Busts a Move](https://tv-fanatic-res.cloudinary.com/iu/s--Pkcdrny1--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371219399/sheldon-busts-a-move.png)
When Priya uses her lawyer skills to pick apart the roommate agreement, the girls take Sheldon dancing on this episode of TBBT.
![Sheldon and Amy Photo](https://tv-fanatic-res.cloudinary.com/iu/s--sOjwzCM---/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371219014/sheldon-and-amy-photo.png)
Sheldon and Amy spread gossip this week. Elsewhere, Howard takes a big step in his relationship with Bernadette.
![Nerds on a Mission](https://tv-fanatic-res.cloudinary.com/iu/s--W0EFRUG3--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371219013/nerds-on-a-mission.png)
Someone has the gall to hack into Sheldon's online game account this week. The guy go on a search to find out who would dare do such a thing.
![Hi, Couple!](https://tv-fanatic-res.cloudinary.com/iu/s--hNfiKg4t--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371218551/hi-couple.png)
Wolowitz baffles Sheldon this week with a magic trick. Elsewhere, Leonard realizes that there's a problem with him dating Priya.
![The Toast Derivation Scene](https://tv-fanatic-res.cloudinary.com/iu/s--gUUOhtgR--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371218386/the-toast-derivation-scene.png)
Sheldon struggles with a realization on this episode: Leonard who is actually the center of the social group.
![The Cohabitation Formulation Scene](https://tv-fanatic-res.cloudinary.com/iu/s--kYfPYI63--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371217969/the-cohabitation-formulation-scene.png)
Wolowitz considers going all the way with Bernadette this week. Elsewhere, Leonard rekindles his relationship with Raj's sister.
![The Benefactor Factor Scene](https://tv-fanatic-res.cloudinary.com/iu/s--ouoghEF0--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371218201/the-benefactor-factor-scene.png)
A donor is willing to give Leonard a lot of money this week. In exchange for sex from him, that is.
![Koothrappali Fantasy](https://tv-fanatic-res.cloudinary.com/iu/s--1_n1Z1eA--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371217603/koothrappali-fantasy.png)
Sheldon gets acting lessons from Penny on this episode. Elsewhere, Koothrappali fantasizes about his best friend's gal.
![Rick Fox on The Big Bang Theory](https://tv-fanatic-res.cloudinary.com/iu/s--i4BKyqHz--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371217397/rick-fox-on-the-big-bang-theory.png)
There's tension at a hotel this week. That's because the group runs into Bernadette's ex-boyfriend during a science event.
![The Bus Pants Utilization Scene](https://tv-fanatic-res.cloudinary.com/iu/s---SKmvt27--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371217138/the-bus-pants-utilization-scene.png)
Leonard gets an idea for a smart phone application on this episode. How does that go? Find out now.
![As the Justice League](https://tv-fanatic-res.cloudinary.com/iu/s--FVf8LL5i--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371216646/as-the-justice-league.png)
The guys find a use for Penny's boyfriend this week, as they enter a costume contest and they go as the Justice League members.
![Penny, Bernadette and Amy](https://tv-fanatic-res.cloudinary.com/iu/s--UotmDjJT--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371216429/penny-bernadette-and-amy.png)
Amy realizes she has sexual feelings for Penny's ex on this episode. That's awkward. Meanwhile, Koothrappali and Wolowitz attempt to prove who would be the better superhero.
![Keith Carradine on TBBT](https://tv-fanatic-res.cloudinary.com/iu/s--4335Hsw_--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371216052/keith-carradine-on-tbbt.png)
Penny asks Leonard to fib to her father this week. Elsewhere, Howard, Raj and Bernadette go for an all-nighter with a telescope.
![Return of Wil Wheaton](https://tv-fanatic-res.cloudinary.com/iu/s--0JyuqxJ8--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371215669/return-of-wil-wheaton.png)
Wil Wheaton is back this week! He causes problems for the guys when they try to see a movie. Elsewhere, Penny and Bernadette invite Amy to a sleepover.
![Pretty, Funny Guest Star](https://tv-fanatic-res.cloudinary.com/iu/s--xqhVpHFN--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371215418/pretty-funny-guest-star.png)
Sheldon places Wolowitz's security clearance in danger this week. How so? By answering questions from an agent played by Eliza Dushku.
![The Irish Pub Formulation Scene](https://tv-fanatic-res.cloudinary.com/iu/s--9kQAPeg0--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371215204/the-irish-pub-formulation-scene.png)
A major secret abounds this week, as Leonard keeps quiet about an affair with Raj's sister. Will Sheldon keep the secret?
![Amy with Sheldon](https://tv-fanatic-res.cloudinary.com/iu/s--W8LJrxOb--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371214942/amy-with-sheldon.png)
Amy wants to introduce Sheldon to her mother on this episode. Meanwhile, Leonard is down on himself as he comes to terms with the fact that all the other guys have girlfriends.
![Big Bang Guest Stars](https://tv-fanatic-res.cloudinary.com/iu/s--RM4yrh-A--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371214706/big-bang-guest-stars.png)
We learn of an embarrassing secret about Wolowitz this week. How is that for a tease?!? Read our recap to learn more.
![The Zazzy Substitution Scene](https://tv-fanatic-res.cloudinary.com/iu/s--rkZHE9VP--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371214475/the-zazzy-substitution-scene.png)
The focus of this week's episode: Sheldon's search for an alternative to human companionship. Read on to see how that goes.
![A Sheldon Diagram](https://tv-fanatic-res.cloudinary.com/iu/s--tEO-lYaU--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371214162/a-sheldon-diagram.png)
By the time he downloads his consciousness into a robot body, Sheldon realizes he'll be long gone. As a result, he attempts to make himself live longer.
![Feelin Good](https://tv-fanatic-res.cloudinary.com/iu/s--alvwNBDP--/t_small_l/cs_srgb,d_tv-fanatic-placeholder-square.png,f_auto,fl_strip_profile.lossy,q_auto:420/v1371213041/feelin-good.png)
Penny tags along for Sheldon's first date on the fourth season premiere. Elsewhere, Wolowitz discovers a new use for a robotic arm.