Best 'Big Bang Theory' episodes of all time
For 12 seasons, "The Big Bang Theory" delighted audiences with the antics and misadventures of four nerds and the women who have learned to love them. The CBS sitcom originally focused on a quartet of brilliant, yet socially awkward scientists—Leonard Hofstadter (Johnny Galecki), Sheldon Cooper (Jim Parsons), Howard Wolowitz (Simon Helberg), and Raj Koothrappali (Kunal Nayyar)—as well as their next-door neighbor, an attractive woman with street smarts named Penny (Kaley Cuoco).
Over the years, the gang grew to include three more members: neuroscientist Amy Farrah Fowler (Mayim Bialik), microbiologist Bernadette Rostenkowski (Melissa Rauch), and comic book store owner Stuart Bloom (Kevin Sussman). As the cast expanded so did fans' love for the show. Over the course of its run, the series consistently ranked among the best shows on TV and was nominated for 55 Emmy Awards.
The series' end also made way for the very successful prequel "Young Sheldon," the series finale of which aired in May 2024. The spin-off delved deeper into the fascinating character of Sheldon Cooper in his younger years and the events that led to the enigmatic persona we see on "The Big Bang Theory"; the final season of the show also saw Jim Parsons reprising his role as adult Sheldon. Another spin-off, titled "Georgie and Mandy's First Marriage," premiered on Oct. 17, 2024 and follows Sheldon's older brother, Georgie (Montana Jordan). Two weeks after its debut, CBS announced that the series had been picked up for a full season, so fans can look forward to many more misadventures from the Cooper family into 2025.
Audiences also have plenty of favorite moments from "The Big Bang Theory" to rewatch—like when the guys go to Vegas, any moment involving sports, Wolowitz getting stuck in a robotic arm, and Sheldon's rivalry with Leslie Winkle, to name a few. But with almost 280 episodes to choose from, it's still challenging to pick those favorites out of the bunch. To help drill down to a list of the all-time bests, Stacker has ranked the top 50 episodes by IMDb user ratings, with ties broken by the number of votes.
#50. The Locomotive Manipulation
- IMDb user rating: 8.2
- Season 7, episode 15
- Air date: Feb. 6, 2014
This season seven episode found Sheldon, Amy, Howard, and Bernadette taking a Valentine's Day train ride to Napa Valley, while Leonard and Penny take Raj's dog, Cinnamon, to the vet when she accidentally eats some chocolate. The episode marks Sheldon and Amy's first sustained, romantic kiss, which for fans was a long time coming.
#49. The Earworm Reverberation
- IMDb user rating: 8.3
- Season 9, episode 10
- Air date: Dec. 10, 2015
Sheldon gets a tune stuck in his head that he can't quite place, despite his eidetic memory. While he worries he's going crazy, Raj and Howard set out in search of their band's single Facebook fan. By the end of the half-hour, Sheldon has identified the mysterious song as the Beach Boys' "Darlin'" and draws a life-changing connection between the upbeat melody and his ex-girlfriend, Amy.
#48. The Agreement Dissection
- IMDb user rating: 8.3
- Season 4, episode 21
- Air date: April 28, 2011
Leonard's new girlfriend Priya begins pointing out holes in the roommate agreement, much to Sheldon's chagrin. In order to take his mind off his aggravation, Penny invites Sheldon along on a girls' night, where he kisses Amy.
#47. The Love Car Displacement
- IMDb user rating: 8.3
- Season 4, episode 13
- Air date: Jan. 20, 2011
The gang road-trips to a science convention in Big Sur. When Howard meets one of Bernadette's ex-boyfriends at the event, he begins to spiral, which prompts a number of other meltdowns among the group. As the week continues, the friends begin a complicated game of musical beds, which leaves most of them wishing they'd never left home in the first place.
#46. The Re-Entry Minimization
- IMDb user rating: 8.3
- Season 6, episode 4
- Air date: Oct. 18, 2012
Amy, Penny, and Leonard embark on a game night with Sheldon, whose tendency to overthink things is out in full force. Meanwhile, Wolowitz returns from space to a sickly Bernadette.
#45. The Psychic Vortex
- IMDb user rating: 8.3
- Season 3, episode 12
- Air date: Jan. 11, 2010
Penny is mocked when the guys discover that she believes in psychics and gets especially angry at Leonard for being so judgemental. Meanwhile, Sheldon accepts a bribe to be Raj's wingman at a university mixer, where one of the girls instead takes a liking to him instead of Raj.
#44. The Excelsior Acquisition
- IMDb user rating: 8.3
- Season 3, episode 16
- Air date: March 1, 2010
After rushing Penny to the hospital, Sheldon finds himself in court for a traffic violation. While settling the matter of the ticket, he misses an autograph signing with his hero, Stan Lee, a travesty Penny vows to rectify.
#43. The Parking Spot Escalation
- IMDb user rating: 8.3
- Season 6, episode 9
- Air date: Nov. 29, 2012
Wolowitz delivers one of his biggest Sheldon no-no's by placing his bare bottom on Sheldon's sacred spot on the couch. Wolowitz gets the use of Sheldon's university parking spot following his celebrity as an astronaut; Sheldon gets jealous and a battle ensues. Amy has her first experience with bikini waxing. She may have lost weight from the ordeal, but that is nothing compared to the shade that Bernadette sends her way when they take sides with their manly men. Penny tries to calm the moment, but she's more successful at relieving her bottle of wine.
#42. The Creepy Candy Coating Corollary
- IMDb user rating: 8.3
- Season 3, episode 5
- Air date: Oct. 19, 2009
Leonard and the guys (sans Sheldon) has a deal: If one of them gets a girlfriend, they must work to set the others up. Penny reluctantly agrees to set up Wolowitz with Bernadette. Although their love connection isn't instant, they bond on account of their mutually difficult mothers.
#41. The Monopolar Expedition
- IMDb user rating: 8.3
- Season 2, episode 23
- Air date: May 11, 2009
Penny learns that the guys are about to go on an extended trip to the North Pole when Sheldon asks if they can use the freezer at The Cheesecake Factory to prepare for the cold climate. True to form, the guys didn't really think it through before they ventured into the giant appliance. Elsewhere, the romantic tension between Leonard and Penny continues to escalate in a way that's on par with the first Ross and Rachel kiss on "Friends."
#40. The Maternal Congruence
- IMDb user rating: 8.3
- Season 3, episode 11
- Air date: Dec. 14, 2009
Leonard's mother, Beverly, comes to visit, opening a huge can of worms when Leonard realizes she's closer with his roommate than she is with him. Penny attempts to smooth things over by pushing Beverly to be more emotionally expressive, a state that goes against Beverly's very nature.
#39. The Electric Can Opener Fluctuation
- IMDb user rating: 8.3
- Season 3, episode 1
- Air date: Sep. 21, 2009
The guys return from the North Pole, and not a moment too soon. Spending so much time with Sheldon in a remote place drove the others to madness, causing them to mess with his data to keep him happy. Hurt that his friends would lie to him, he retreats to Texas—which throws a wrench in Leonard's plans to finally get romantic with Penny.
#38. The Peanut Reaction
- IMDb user rating: 8.3
- Season 1, episode 16
- Air date: May 12, 2008
After learning that Leonard has never had a birthday party, Penny plans a surprise celebration for him. Wolowitz goes to extreme measures to attempt to get Leonard to the party.
#37. The Bat Jar Conjecture
- IMDb user rating: 8.3
- Season 1, episode 13
- Air date: April 21, 2008
Sheldon's hubris gets him kicked off the University Physics Bowl team, and the guys replace him with Leslie Winkle. Penny later challenges the roommates to another kind of trivia test.
#36. The Big Bran Hypothesis
- IMDb user rating: 8.3
- Season 1, episode 2
- Air date: Oct. 1, 2007
In an effort to impress new neighbor Penny, Leonard offers to help her complete her move-in. Upon seeing her disorganized apartment, Sheldon is compelled to clean it without her permission while she is sleeping in the next room. Not surprisingly, it doesn't turn out well—and Sheldon gets a needed lesson in sarcasm.
#35. The Bakersfield Expedition
- IMDb user rating: 8.4
- Season 6, episode 13
- Air date: Jan. 10, 2013
En route to Comic-Con, while dressed in full costume to do a photoshoot in the middle of the desert, Leonard's car gets stolen. The ladies use the time to discover what's great about comic books.
#34. The Romance Resonance
- IMDb user rating: 8.4
- Season 7, episode 6
- Air date: Oct. 24, 2013
Most members of the gang have issues when it comes to romantic gestures. Wolowitz turns out to be the exception when he sings his love for the temporarily quarantined Bernadette.
#33. The Egg Salad Equivalency
- IMDb user rating: 8.4
- Season 6, episode 12
- Air date: Jan. 3, 2013
Leonard is getting a little too much attention from Alex, Sheldon's attractive research assistant, and Penny isn't happy about it. Sheldon attempts to help, which gets all of the guys sent to the university's HR department for being a little too honest about their previous actions and words.
#32. The Pants Alternative
- IMDb user rating: 8.4
- Season 3, episode 18
- Air date: March 22, 2010
Sheldon has to overcome his fear of public speaking in order to accept an award and is given some very bad advice by the group. He drinks too much wine and ends up embarrassing himself—and the university—with a whole new view of "Uranus."
#31. The Vengeance Formulation
- IMDb user rating: 8.4
- Season 3, episode 9
- Air date: Nov. 23, 2009
Kripke delivers a worthwhile prank while Sheldon is on the radio, so Sheldon and the team plot revenge. Wolowitz and Bernadette consider taking their relationship to the next level.
#30. The Cruciferous Vegetable Amplification
- IMDb user rating: 8.4
- Season 4, episode 2
- Air date: Sep. 30, 2010
Sheldon realizes that he won't live long enough to download his consciousness into a robot to achieve immortality, so he takes steps to be healthier—including eating better and going running with Penny. In order to eliminate unnecessary risks, he develops a "Mobile Virtual Presence Device" that he controls from his bedroom.
#29. The Euclid Alternative
- IMDb user rating: 8.4
- Season 2, episode 5
- Air date: Oct. 20, 2008
Weary of driving him around all of the time, the gang forces Sheldon to get his driver's license—but he doesn't quite impress at the DMV. Octavia Spencer makes an appearance as a DMV employee who has to deal with Sheldon.
#28. The Middle Earth Paradigm
- IMDb user rating: 8.4
- Season 1, episode 6
- Air date: Oct. 29, 2007
In another episode that nods to Tolkien, Penny invites the guys to her Halloween party (after the guys get bullied by some teenagers). While at the shindig, Leonard finds himself in a threatened position with Penny's ex-boyfriend, Kurt. But ultimately, Penny and Leonard share a moment and get closer.
#27. The Countdown Reflection
- IMDb user rating: 8.5
- Season 5, episode 24
- Air date: May 10, 2012
In this heartwarming season finale, Wolowitz is about to go into outer space, and Bernadette reflects on their relationship. He gives her a touching gift and she decides that she wants to get married before his launch—so the gang jumps through hoops to give them a beautiful wedding before lift-off.
#26. The Boyfriend Complexity
- IMDb user rating: 8.5
- Season 4, episode 9
- Air date: Nov. 18, 2010
This episode involves Penny asking Leonard to pose as her boyfriend when her dad comes to town. Not knowing that this is a charade, Sheldon demands changes be made to the roommate agreement. Wolowitz tries to get Raj and Bernadette to bond over some wine in the lab and Raj takes the moment a bit too far.
#25. The 43 Peculiarity
- IMDb user rating: 8.5
- Season 6, episode 8
- Air date: Nov. 15, 2012
Raj and Wolowitz are determined to know where Sheldon vanishes to for 20 minutes every day uttering the number 43, so they stalk him in order to find out what he's doing. Meanwhile, Leonard is jealous of Penny's new study partner, and Sheldon's research assistant Alex enlightens him to the fact that people do not always realize when they are being flirted with.
#24. The Precious Fragmentation
- IMDb user rating: 8.5
- Season 3, episode 17
- Air date: March 8, 2010
The guys return from a garage sale with a bunch of cool stuff, including one of the actual rings used in "Lord of the Rings." What could possibly go wrong? Naturally, all want to take possession of it, but Leonard ultimately suggests sending it back to Peter Jackson.
#23. The Einstein Approximation
- IMDb user rating: 8.5
- Season 3, episode 14
- Air date: Feb. 1, 2010
Sheldon is stumped by a tough physics question and has been losing sleep over it. His constant obsessing is driving his pals crazy as he tries a series of stunts to solve the problem—like going into a children's ball pit at the mall and working with Penny at The Cheesecake Factory.
#22. The Gorilla Experiment
- IMDb user rating: 8.5
- Season 3, episode 10
- Air date: Dec. 7, 2009
Now that Bernadette has joined the crew, Penny feels out of touch during their frequent conversations about physics. She wants to learn more so she can impress Leonard and show that she cares about his work. Penny asks Sheldon to give her a tutorial, but his lesson is a bit more than she bargained for.
#21. The Vegas Renormalization
- IMDb user rating: 8.5
- Season 2, episode 21
- Air date: April 27, 2009
Wolowitz is left devastated after his break up with Leslie, so Leonard and Raj take him to Vegas to help lift his spirits. At home, Sheldon accidentally gets locked out of his apartment and turns to Penny for comfort. They attempt to bond—and (sort of) succeed.
#20. The Tangerine Factor
- IMDb user rating: 8.5
- Season 1, episode 17
- Air date: May 19, 2008
Sheldon believes a conspiracy is afoot—that his favorite Chinese restaurant isn't using the right ingredients. Meanwhile, Penny is humiliated when an old beau posts intimate details online and finally agrees to go on a date with Leonard. This episode is also the first time we see a Schrödinger's Cat reference in the show.
#19. The Long Distance Dissonance
- IMDb user rating: 8.6
- Season 10, episode 24
- Air date: May 11, 2017
Dr. Ramona Nowitzki has returned, and she still has a thing for Sheldon. To complicate matters, Amy is away at Princeton. The gang does their best to keep her away from Sheldon as they know she is up to no good. The episode ends on a heartwarming note with Sheldon making a surprise visit to Amy.
#18. The Roommate Transmogrification
- IMDb user rating: 8.6
- Season 4, episode 24
- Air date: May 19, 2011
Raj rushes out of his apartment when his sister Priya and Leonard are having a "Star Trek"-themed romantic moment. He moves in with Sheldon, who is initially appalled, but ends up being delighted by Raj's considerate behavior. Wolowitz feels he needs to "man up" when Bernadette earns her doctorate degree and gets a high-paying job in a scientific field. And in a strange turn, Raj and Penny have an ill-advised romantic moment.
#17. The Lunar Excitation
- IMDb user rating: 8.6
- Season 3, episode 23
- Air date: May 24, 2010
After a bad date, Penny realizes that Leonard's intelligence has made an impression on her and she can't deal with vapid men anymore. This leads to an awkward romantic encounter that leaves Leonard confused, and he turns to Leslie Winkle for comfort—she doesn't give it to him. On the Sheldon front, the guys decide to create a dating profile for him and they're shocked when Amy responds.
#16. The Hawking Excitation
- IMDb user rating: 8.6
- Season 5, episode 21
- Air date: April 5, 2012
Sheldon finally gets to meet his idol Stephen Hawking. The only problem is that Wolowitz has the key to this introduction—and because Sheldon was rude to him, Wolowitz makes him jump through many hoops in order to meet the famous physicist.
#15. The Good Guy Fluctuation
- IMDb user rating: 8.6
- Season 5, episode 7
- Air date: Oct. 27, 2011
Leonard is flattered when an attractive comic book artist takes an interest in him, but there's a problem—he's dating Priya. He decides to turn to Penny for advice. And as it's Halloween, the guys take great pleasure in giving Sheldon a fright.
#14. The Justice League Recombination
- IMDb user rating: 8.7
- Season 4, episode 11
- Air date: Dec. 16, 2010
In another holiday episode, Penny is dating her former ex—the attractive but dimwitted Zack—and they agree to go to a New Year's Eve costume party at the comic book shop dressed as the Justice League. She is at first reluctant to go, hinting that she is not over Leonard, but she dons a wig and ventures to the party anyway.
#13. The Robotic Manipulation
- IMDb user rating: 8.7
- Season 4, episode 1
- Air date: Sep. 23, 2010
Penny is pressured into being a third wheel on Sheldon and Amy's first date. Meanwhile, Wolowitz comes up with an unintended use for a robotic arm that lands him in the ER.
#12. The Scavenger Vortex
- IMDb user rating: 8.7
- Season 7, episode 3
- Air date: Oct. 3, 2013
Raj develops a scavenger hunt. Leonard isn't subtle about his disinterest in partnering with Penny, because he thinks it would be a disadvantage. The friends draw names and form groups of two, before setting off to solve 10 puzzles.
#11. The Panty Piñata Polarization
- IMDb user rating: 8.7
- Season 2, episode 7
- Air date: Nov. 10, 2008
This episode has Raj and Wolowitz devising a way to find the spot where "America's Next Top Model" is taped, in hopes of winning over a rejected former contestant. Penny and Sheldon are at war; he's trying to get her to stop piggybacking off their internet service. But Penny has a decisive victory after making an important phone call.
#10. The Barbarian Sublimation
- IMDb user rating: 8.7
- Season 2, episode 3
- Air date: Oct. 6, 2008
Single, underemployed, and a little lost, Penny is going through a rough patch. She attempts to turn to Sheldon for help, but he misses the cues and returns to his gaming. This leads Penny to try her hand at computer games, and once she gets a taste for gaming she finds it nearly impossible to stop.
#9. The Thanksgiving Decoupling
- IMDb user rating: 8.8
- Season 7, episode 9
- Air date: Nov. 21, 2013
In this holiday-themed episode, Sheldon is reluctant to spend Thanksgiving with the rest of the gang on account of the hostess: Mrs. Wolowitz. Things are further complicated when Bernadette's dad arrives—Wolowitz awkwardly tries to bond with him, but his father-in-law connects with Sheldon instead. The evening takes another bad turn when Leonard learns that Penny accidentally got married to her ex-boyfriend Zack in Vegas years ago.
#8. The Maternal Capacitance
- IMDb user rating: 8.9
- Season 2, episode 15
- Air date: Feb. 9, 2009
When Leonard's difficult-to-please psychoanalyst mother comes for a visit, he goes out of his way to earn her praise. To cause him further grief, she and Sheldon bond easily. Her overly analytic nature puts the other guys on edge, but her incessant criticism ultimately benefits Leonard and Penny's relationship by causing a bonding moment.
#7. The Adhesive Duck Deficiency
- IMDb user rating: 8.9
- Season 3, episode 8
- Air date: Nov. 16, 2009
Leonard, Raj, and Wolowitz are in the desert planning to watch a meteor shower, but are distracted by some substitute teachers who give them a special gift. Sheldon opts to stay home, but Penny has an accident that forces him to come to her aid. Amid his valiant efforts to get her on the mend, he inadvertently gets to second base. During her recovery, a new version of the fan-favorite "Soft Kitty" song is created.
#6. The Bow Tie Asymmetry
- IMDb user rating: 9.0
- Season 11, episode 24
- Air date: May 10, 2018
In the season 11 finale, Sheldon and Amy finally tie the knot. In the lead-up to their big day, Leonard, Raj, Wolowitz, Bernadette, and Penny are tasked with finalizing details and dealing with the bride and groom's extended family. Tensions reach an all-time high when Sheldon is late to the ceremony, but his reason, and Amy's response, proves once and for all that they're a perfect match for each other.
#5. The Change Constant
- IMDb user rating: 9.0
- Season 12, episode 23
- Air date: May 16, 2019
In the penultimate episode of "The Big Bang Theory," Sheldon and Amy win the Nobel Prize. While their accomplishment should bring joy it also opens the door to a number of other emotions, including frustration, fear, and sadness. Meanwhile, the building's elevator is finally fixed after a decade of being out of service.
#4. The Staircase Implementation
- IMDb user rating: 9.0
- Season 3, episode 22
- Air date: May 17, 2010
Leonard recounts the tale of how he ended up living with Sheldon, despite lots of warning signs that this may not be a great idea. Also, the mystery of the broken elevator is finally addressed.
#3. The Opening Night Excitation
- IMDb user rating: 9.0
- Season 9, episode 11
- Air date: Dec. 17, 2015
Sheldon missed the fact that the opening of the new "Star Wars" film coincided with Amy's birthday. He lets Penny and Bernadette know that he planned a very special birthday gift: taking their relationship to a physical level.
#2. The Bath Item Gift Hypothesis
- IMDb user rating: 9.1
- Season 2, episode 11
- Air date: Dec. 15, 2008
In the second highest-rated episode of the series, it's Christmas time and Sheldon is grappling with the stress of gift-giving. But knowing that Penny has a present for him makes him wonder what to do in order to show an equal amount of thoughtfulness. Leonard has something else on his mind: His handsome, gifted (and somehow non-nerdy) colleague David Underhill takes an instant liking to Penny. Gifts are exchanged and a magical hug is delivered.
#1. The Stockholm Syndrome
- IMDb user rating: 9.5
- Season 12, episode 24
- Air date: May 16, 2019
In the series finale, set two months after the events of the previous episode, the gang prepares to head to Sweden for the Nobel Prize ceremony. Despite all being in the same place physically, the friends are a world apart mentally— Amy and Leonard have a big secret, Howard and Bernadette worry about their kids, and Raj finally (maybe) gets a girlfriend. In the end, Sheldon's acceptance speech reunites them, and they all fly home to eat takeout in the apartment.
