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 in October 2024 and follows Sheldon's older brother, Georgie (Montana Jordan). CBS picked up the series for a full season, so fans can look forward to many more misadventures from the Cooper family throughout 2025.
Also in late 2024, news broke that another "Big Bang Theory" spin-off series was in the works for Max. Though it has yet to be greenlit as of Jan. 20, 2025, the show would bring back three "Big Bang" recurring actors: Sussman as comic book store owner Stuart Bloom; Lauren Lapkus as the store's manager, Denise; and Brian Posehn as Caltech geologist Bert Kibbler.
Whether or not that series makes it to air, audiences 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 25 episodes by IMDb user ratings as of Jan. 20, 2025, with ties broken by the number of votes.
#25. The Gorilla Experiment
- IMDb user rating: 8.4
- Number of IMDb votes: 4,424
- 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.
#24. The Precious Fragmentation
- IMDb user rating: 8.4
- Number of IMDb votes: 4,425
- 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: 8.4
- Number of IMDb votes: 4,519
- 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 Long Distance Dissonance
- IMDb user rating: 8.5
- Number of IMDb votes: 3,681
- 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.
#21. The Roommate Transmogrification
- IMDb user rating: 8.5
- Number of IMDb votes: 4,160
- 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.
#20. The Countdown Reflection
- IMDb user rating: 8.5
- Number of IMDb votes: 4,247
- 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.
#19. The Hawking Excitation
- IMDb user rating: 8.5
- Number of IMDb votes: 4,394
- 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.
#18. The Vegas Renormalization
- IMDb user rating: 8.5
- Number of IMDb votes: 4,619
- 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.
#17. The Good Guy Fluctuation
- IMDb user rating: 8.5
- Number of IMDb votes: 4,690
- 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.
#16. The Tangerine Factor
- IMDb user rating: 8.5
- Number of IMDb votes: 5,097
- 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.
#15. The Lunar Excitation
- IMDb user rating: 8.6
- Number of IMDb votes: 4,442
- 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.
#14. The Justice League Recombination
- IMDb user rating: 8.6
- Number of IMDb votes: 4,573
- 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 Panty Piñata Polarization
- IMDb user rating: 8.6
- Number of IMDb votes: 5,043
- 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.
#12. The Robotic Manipulation
- IMDb user rating: 8.7
- Number of IMDb votes: 4,926
- 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.
#11. The Scavenger Vortex
- IMDb user rating: 8.7
- Number of IMDb votes: 4,942
- 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.
#10. The Barbarian Sublimation
- IMDb user rating: 8.7
- Number of IMDb votes: 5,344
- 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
- Number of IMDb votes: 5,075
- 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: 8.8
- Number of IMDb votes: 5,270
- 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
- Number of IMDb votes: 5,865
- 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
- Number of IMDb votes: 4,487
- 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
- Number of IMDb votes: 5,327
- 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
- Number of IMDb votes: 5,628
- 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
- Number of IMDb votes: 5,635
- 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
- Number of IMDb votes: 7,385
- 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
- Number of IMDb votes: 11,140
- 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.
