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The Big Bang Theory
The Big Bang Theory (Official Title Card).png
Title screen
Genre Sitcom
Created by
Directed by Mark Cendrowski
Starring
Theme music composer Barenaked Ladies
Opening theme "Big Bang Theory Theme"
Country of origin United States
Original language(s) English
No. of seasons 12
No. of episodes 279 (list of episodes)
Production
Executive producer(s)
  • Chuck Lorre
  • Bill Prady
  • Lee Aronsohn
  • Steven Molaro
  • Eric Kaplan
  • Maria Ferrari
  • Dave Goetsch
  • Steve Holland
Producer(s) Faye Oshima Belyeu
Editor(s) Peter Chakos
Camera setup Multi-camera
Running time 18–22 minutes
Production company(s)
Release
Original network CBS
Original release September 24, 2007 (2007-09-24) – May 16, 2019 (2019-05-16)
Chronology
Related shows

The Big Bang Theory is a popular American sitcom (a funny TV show about everyday life). It was created by Chuck Lorre and Bill Prady for the CBS network. The show aired for 12 seasons, from September 24, 2007, to May 16, 2019, with a total of 279 episodes.

The story first focused on five main characters living in Pasadena, California. These included Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons), who were both physicists at Caltech and shared an apartment. Across the hall lived Penny (Kaley Cuoco), a waitress who dreamed of becoming an actress. Leonard and Sheldon's friends and coworkers, Howard Wolowitz (Simon Helberg), an aerospace engineer, and Raj Koothrappali (Kunal Nayyar), an astrophysicist, were also part of the group. They were all very smart but sometimes struggled with social situations.

As the show continued, other characters became more important. These included Amy Farrah Fowler (Mayim Bialik), a neuroscientist, Bernadette Rostenkowski (Melissa Rauch), a microbiologist, and Stuart Bloom (Kevin Sussman), who owned a comic book store.

The show was filmed in front of a live audience. It was produced by Chuck Lorre Productions and distributed by Warner Bros. Television. While the first season had mixed reviews, later seasons were very popular. Seven seasons were among the top ten most-watched shows. In its eleventh season, it even reached the number one spot.

The Big Bang Theory received many awards and nominations. Jim Parsons won the Emmy Award for Outstanding Lead Actor in a Comedy Series four times for his role as Sheldon. The show also led to other TV series. A prequel, Young Sheldon, told the story of Sheldon's childhood. A new series, Georgie & Mandy's First Marriage, started in October 2024, following Sheldon's older brother, Georgie.

What the Show is About

Early Seasons: Friendships and New Beginnings

The show explores the friendships and relationships of Leonard Hofstadter and Sheldon Cooper, their neighbor Penny, and their friends Howard Wolowitz and Raj Koothrappali. Leonard is immediately interested in Penny when she moves in. He tries to win her over while she dates other people.

The group enjoys science fiction, comic books, and video games. Their shared interests often lead to funny situations because they are not always good at social interactions. Sheldon's strict habits and unique personality often cause funny arguments with Leonard. Howard's awkward behavior and close relationship with his mother also add to the humor. Raj initially finds it hard to talk to women.

Leonard and Penny's relationship grows when Leonard returns from a trip in season three. They start dating seriously. However, they break up when Leonard says he loves Penny, and she isn't ready to say it back. Leonard then dates Raj's sister, Priya, which causes some tension in the group.

Middle Seasons: New Friends and Growing Up

The show's main group gets bigger with the arrival of Amy Farrah Fowler and Bernadette Rostenkowski. Amy is a neurobiologist who meets Sheldon through online dating. Bernadette is a microbiologist who starts dating Howard. These new characters bring fresh stories and help the original characters grow.

Sheldon and Amy's relationship slowly changes from just an intellectual connection to a romantic one. Sheldon gradually learns to be more comfortable with physical touch and showing emotions. Their relationship is often funny because they approach romance like a science experiment.

Howard's relationship with Bernadette helps him become more mature. He becomes less dependent on his mother. They get married in the fifth season. Soon after, Howard goes on a space mission to the International Space Station.

Leonard and Penny get back together. Their relationship faces challenges, like Leonard's worries and Penny's career struggles. Penny initially turns down Leonard's marriage proposals because she feels unprepared. They continue to grow and understand each other better.

Final Seasons: Marriage and Future Plans

The last seasons focus on the characters getting married and settling down. Leonard and Penny finally marry in the ninth season. They move into their own apartment when Sheldon moves out.

Sheldon and Amy's relationship reaches big milestones. They become more intimate on Amy's birthday and later move in together. After a brief breakup, they get back together and get engaged. Their wedding in season eleven shows how much Sheldon has grown. He learns to be more open and capable of love.

The series ends with the characters finding personal and professional happiness. Penny becomes pregnant in the final season, suggesting a new family for her and Leonard. The series finale shows Sheldon and Amy winning the Nobel Prize in Physics. This highlights their scientific achievements and the strong friendships that supported them.

Main Characters

The Big Bang Theory Cast
Main characters in The Big Bang Theory season 6. From left: Rajesh Koothrappali, Leonard Hofstadter, Penny, Sheldon Cooper, Howard Wolowitz, Bernadette Rostenkowski-Wolowitz, and Amy Farrah Fowler.
  • Johnny Galecki as Leonard Hofstadter: An experimental physicist with a very high IQ. He earned his Ph.D. at 24. Leonard loves video games, comic books, and Dungeons & Dragons. He shares an apartment with Sheldon in Pasadena, California. Leonard is immediately smitten with his neighbor Penny, and they eventually marry.
  • Jim Parsons as Sheldon Cooper: A child genius from Galveston, Texas. Sheldon started college at age eleven and got his Ph.D. at sixteen. He is a theoretical physicist studying quantum mechanics and string theory. Despite his very high IQ, he often struggles with understanding social situations. He likes things done his way and often boasts about his intelligence. He has a very strict routine. Despite his quirks, he starts a relationship with Amy Farrah Fowler, and they eventually marry.
  • Kaley Cuoco as Penny: An aspiring actress from Omaha, Nebraska. Penny moves in across the hall from Sheldon and Leonard. She works as a waitress at The Cheesecake Factory. Later, she becomes a pharmaceutical sales representative. Penny becomes close friends with Bernadette and Amy. Penny and Leonard form a relationship and eventually marry.
  • Simon Helberg as Howard Wolowitz: An aerospace engineer who earned his master's degree at Massachusetts Institute of Technology. Howard is Jewish and lived with his mother. Unlike his friends, Howard does not have a doctorate. He trains to be an astronaut and travels to the International Space Station. Howard initially tries to impress women, but he later dates Bernadette, and they get married.
  • Kunal Nayyar as Rajesh Koothrappali: A particle astrophysicist from New Delhi, India. Raj initially had selective mutism, meaning he couldn't talk to women unless he was relaxed. Raj often has very sensitive tastes. He later overcomes his selective mutism. He dates Emily Sweeney and later has an on-again, off-again engagement with Anu. He also has a Yorkshire Terrier named Cinnamon.
  • Melissa Rauch as Bernadette Rostenkowski-Wolowitz: A young woman who first works with Penny at The Cheesecake Factory to pay for graduate school. She studies microbiology. Penny introduces Bernadette to Howard. They initially don't get along but later date, get engaged, and marry. Bernadette is usually sweet but can be very strong-willed when upset.
  • Mayim Bialik as Amy Farrah Fowler: A neurobiologist from Glendale, California. She is matched with Sheldon through an online dating site. Like Sheldon, she initially struggles with social skills. After becoming friends with Penny and Bernadette, she becomes more interested in social and romantic interactions. Her relationship with Sheldon slowly grows, and they eventually marry. Amy believes she and Penny are best friends.
  • Kevin Sussman as Stuart Bloom: The kind and often unsure owner of a comic book store. Stuart is a talented artist. He is socially awkward but has slightly better social skills than some of the main group. Stuart often struggles financially, and his comic book store sometimes serves as his home. He later helps care for Howard's mother.

Episodes

The Big Bang Theory logo.

The Big Bang Theory is a super popular American TV show called a sitcom. It was created by Chuck Lorre and Bill Prady for the CBS network. The show is about a group of very smart friends who are scientists and their adventures. It mixes science, friendship, and lots of laughs!

The show ran for many years, starting on September 24, 2007, and ending on May 16, 2019. You can watch all the seasons and episodes on DVD, Blu-ray, and streaming services like Max.

What is The Big Bang Theory About?

The Big Bang Theory focuses on a group of friends who are brilliant scientists. They work at a university and spend their time doing amazing research. Their lives get even more interesting when a new neighbor moves in across the hall.

The main characters are often seen playing video games, reading comic books, and talking about science. The show finds humor in their smart but sometimes socially awkward ways. It also shows how they learn about life and friendship from each other.

How Episodes Get Their Names

One cool thing about The Big Bang Theory is how its episodes are named. Almost every episode title starts with "The." After "The," the title usually sounds like a scientific idea, a theory, or an experiment.

For example, an episode might be called "The Bathtub Gravitation." This title often gives a funny hint about what will happen in that episode. It's a clever way to connect the show's science theme with its funny stories.

Why The Show Was So Popular

The Big Bang Theory became one of the most-watched TV shows. Millions of people tuned in every week to see what the characters would do next. Its humor and relatable characters made it a favorite for many families.

The show was loved because it made science cool and funny. It showed that being smart can be awesome and that friendships come in all forms. It also had many memorable catchphrases and running gags that fans loved.

How the Show Was Made

TBBT logo
Series' logo used for print

The first episode of The Big Bang Theory aired on September 24, 2007. This was actually the second pilot episode made for the show. An earlier pilot was created but never shown to the public. In that first pilot, only Leonard (Johnny Galecki) and Sheldon (Jim Parsons) were main characters. They were named after Sheldon Leonard, a famous TV producer and actor. The first pilot also had two different female lead characters.

The creators, Chuck Lorre and Bill Prady, were given a chance to rework the show. They brought in Kaley Cuoco as Penny, replacing the earlier female characters. Chuck Lorre said that Johnny and Jim were perfect from the start. The reworked pilot led to CBS ordering 13 episodes on May 14, 2007. The show was filmed in front of a live audience.

The show was very successful and was renewed multiple times. In 2009, it was renewed for two more years. In 2011 and 2014, it received three-year renewals. In 2017, it was renewed for two more seasons, bringing the total to 12 seasons, ending in 2019.

Many actors on The Big Bang Theory had worked together before on the sitcom Roseanne. This included Johnny Galecki, Sara Gilbert, and Laurie Metcalf (who plays Sheldon's mother). Chuck Lorre was also a writer for Roseanne.

Science Experts

David Saltzberg, a physics and astronomy professor at University of California, Los Angeles, helped with the show. He checked scripts and provided scientific details, math equations, and diagrams used as props. Sheldon often had real equations on whiteboards in his apartment. Saltzberg was the science consultant for six seasons and attended every filming. He made sure the science was accurate.

Saltzberg sometimes worked with Mayim Bialik, who has a Ph.D. in neuroscience, on biology topics for the show.

Theme Song

The Canadian band Barenaked Ladies wrote and recorded the show's theme song. The song describes the history of the universe and Earth. The band's co-lead singer, Ed Robertson, was asked to write the song after the show's producers saw him perform. Robertson had recently read a book about the Big Bang. He agreed to write the song only after learning that no one else had been asked.

A longer version of the song was released in October 2007. The song was also included on the band's greatest hits album.

Actors' Pay

For the first three seasons, the main actors, Johnny Galecki, Jim Parsons, and Kaley Cuoco, earned up to $60,000 per episode. Their salaries increased over time. By the seventh season, they were earning $350,000 per episode. In 2013, Mayim Bialik and Melissa Rauch also renegotiated their contracts, increasing their pay.

Before season eight, the main five actors (Galecki, Parsons, Cuoco, Helberg, and Nayyar) renegotiated their contracts again. They aimed for around $1 million per episode. In August 2014, the three main actors signed deals for an estimated $1 million per episode for three years. Simon Helberg and Kunal Nayyar also got significant pay raises. By season 10, Helberg and Nayyar also reached the $1 million per episode pay.

In March 2017, the main cast members took a 10 percent pay cut. This allowed Mayim Bialik and Melissa Rauch to receive an increase in their earnings. By April, Bialik and Rauch signed deals to earn $500,000 per episode each.

Repeated Ideas and Jokes

Science in the Show

A lot of the show focuses on science, especially physics. The four main male characters work at Caltech and have science jobs. Bernadette and Amy also work in science. The characters often talk about scientific theories and make science-related jokes.

Science sometimes affects their relationships. For example, Leslie breaks up with Leonard because of a disagreement about physics theories. When Leonard goes on an Arctic research trip, it affects his budding relationship with Penny. Sheldon and Amy even briefly break up over an argument about which of their science fields is better.

Many famous scientists have appeared on the show as guest stars. These include Nobel laureates George Smoot and Frances Arnold. Theoretical physicist Brian Greene and astrophysicist Neil deGrasse Tyson have also appeared. Cosmologist Stephen Hawking made several guest appearances. NASA astronauts Michael J. Massimino and Buzz Aldrin also had cameos.

"Nerd" Culture

6.29.13WilWheatonByLuigiNovi1
Star Trek: The Next Generation actor Wil Wheaton plays a fictional version of himself on the show.

The four main male characters are big fans of "nerd culture." They love science fiction, fantasy, comic books, and collecting related items.

Star Trek is often mentioned. Sheldon especially loves the character of Spock. He is thrilled when Penny gives him a napkin signed by Leonard Nimoy, who played Spock. Star Trek: The Original Series actors William Shatner and George Takei have made guest appearances. Leonard Nimoy also voiced Sheldon's Spock action figure. Star Trek: The Next Generation actors Brent Spiner and LeVar Burton have appeared. Wil Wheaton plays a fictional version of himself in recurring roles. Leonard and Sheldon sometimes speak in Klingon.

They also enjoy Star Wars, Battlestar Galactica, and Doctor Who. James Earl Jones, Carrie Fisher, and Mark Hamill have made guest appearances. The characters sometimes have different favorite shows, like Sheldon loving Firefly but not liking Leonard's enjoyment of Babylon 5. For fantasy, they often refer to The Lord of the Rings and Harry Potter. Howard can even speak Sindarin, an Elvish language.

Wednesday night is their "comic book night" because new comic books are released then. Their friend Stuart runs the comic book store. The group often dresses up as pop culture characters like The Flash, Aquaman, Superman, Batman, Spock, and Thor.

Various games are shown or mentioned, such as World of Warcraft, Halo, and Mario. They also play fictional games like Mystic Warlords of Ka'a and Rock-paper-scissors-lizard-Spock.

Leonard and Penny's Relationship

A main storyline is the relationship between Leonard and Penny. Leonard is attracted to Penny from the first episode. He often does favors for her, which is a running joke. Penny initially dates other people. Their first serious relationship begins when Leonard returns from a trip to the North Pole in season three. However, they break up when Penny isn't ready to say "I love you" back. Leonard then dates Raj's sister, Priya.

Penny later admits she misses Leonard, and they get back together. Leonard proposes several times, but Penny initially says no. In season six, Penny finally tells Leonard she loves him. Their relationship grows stronger. In season seven, Penny realizes they should marry. Leonard proposes with a ring he has carried for years. They decide to elope to Las Vegas in the season eight finale. Leonard tells Penny about a past mistake during his trip. Despite this, they marry in season nine and are happy. They have a second wedding ceremony for family and friends. In season ten, Sheldon moves out, allowing Penny and Leonard to live alone.

In season twelve, Penny says she doesn't want children, and Leonard supports her. Later, Penny becomes pregnant with Leonard's baby. She changes her mind about wanting children.

Sheldon and Amy's Relationship

In the third season, Raj and Howard sign Sheldon up for online dating. They find neurobiologist Amy Farrah Fowler, who is very similar to Sheldon. They start communicating daily, insisting they are not romantically involved. Sheldon later asks Amy to be his girlfriend and creates a "Relationship Agreement" with rules.

Their relationship slowly becomes more intimate. Sheldon gradually becomes more comfortable with physical contact. In season five, Sheldon takes Amy's hand. In season six, Amy challenges Sheldon to express his feelings, and he does. Sheldon admits he never thought about intimacy with anyone before Amy.

In "The Locomotive Manipulation," Sheldon initiates a kiss with Amy for the first time and finds he enjoys it. He slowly becomes more open. In the season eight finale, Sheldon and Amy argue about commitment. Amy decides she needs to think about their future, unaware Sheldon was about to propose. They break up for a short time in season nine. They reunite and become more intimate on Amy's birthday. In season ten, Amy's apartment floods, and she and Sheldon move in together as an experiment. They decide to make it permanent.

In the season eleven premiere, Sheldon proposes to Amy, and she accepts. They get married in the eleventh-season finale.

"Soft Kitty"

The song "Soft Kitty" is sung by Sheldon, Penny, and Amy in the series. Sheldon says his mother sang it to him when he was sick. The song became very popular because of the show. An episode of Young Sheldon shows Sheldon's mother, Mary, singing the song to him when he has the flu.

Howard's Mother

Howard often talks to his mother by shouting from room to room. She is rarely seen, but her voice (provided by Carol Ann Susi until her death) is heard. She is very protective of Howard and sometimes tries to make him feel guilty. Howard is also very attached to her. Until Howard married Bernadette, his close relationship with his mother was a running joke. In season eight, Howard's mother passes away, which deeply affects Howard and Stuart.

Broken Elevator

In the apartment building where Sheldon, Leonard, and Penny live, the elevator is broken for most of the series. This means characters always have to use the stairs. Conversations on the stairs are a common part of almost every episode. The episode "The Staircase Implementation" reveals that Leonard broke the elevator while experimenting with rocket fuel. In one of the final episodes, the elevator is finally fixed.

Where to Watch

TV and Streaming

The Big Bang Theory first aired in the United States on September 24, 2007, on CBS. It also debuted in Canada on CTV in 2007. In the United Kingdom, it started airing on E4 and Channel 4 in 2008.

In May 2010, the show was picked up for syndication, meaning it could be shown on other local TV stations. TBS also got the rights to show reruns on cable. In September 2019, HBO Max (now Max) got the exclusive streaming rights in the U.S. In December 2024, Paramount Global also got non-exclusive cable rights for Nick at Nite and MTV. Since 2025, The Big Bang Theory has also been available on Disney+ in some regions.

DVDs and Blu-rays

The show's seasons have been released on DVD and Blu-ray.

Name No. of
episodes
Release dates
Region 1 Region 2 Region 4
The Complete First Season 17 September 2, 2008 January 12, 2009 April 3, 2009
The Complete Second Season 23 September 15, 2009 October 19, 2009 March 3, 2010
The Complete Third Season 23 September 14, 2010 September 27, 2010 October 13, 2010
The Complete Fourth Season 24 September 13, 2011 September 26, 2011 October 5, 2011
The Complete Fifth Season 24 September 11, 2012 September 3, 2012 October 3, 2012
The Complete Sixth Season 24 September 10, 2013 September 2, 2013 October 11, 2013
The Complete Seventh Season 24 September 16, 2014 September 8, 2014 September 17, 2014
The Complete Eighth Season 24 September 15, 2015 September 14, 2015 September 16, 2015
The Complete Ninth Season 24 September 13, 2016 August 29, 2016 August 31, 2016
The Complete Tenth Season 24 September 12, 2017 September 11, 2017 September 13, 2017
The Complete Eleventh Season 24 September 11, 2018 September 24, 2018 September 12, 2018
The Twelfth and Final Season 24 November 12, 2019 November 11, 2019 November 13, 2019
The Complete Series 279 November 12, 2019 November 11, 2019 November 13, 2019

The first two seasons were only available on DVD at first. Starting with the third season, Blu-ray sets were also released. In 2012, Warner Bros. released the first two seasons on Blu-ray, making all episodes available in that format.

Merchandise

In March 2014, a Lego Ideas project for a Big Bang Theory living room scene with mini-figures gained enough support to be considered by Lego. The set was approved and released in August 2015.

Other Shows from the Big Bang Theory World

Young Sheldon

In November 2016, news came out about a spin-off show focusing on Sheldon as a young boy. This prequel series, called Young Sheldon, is a family comedy. It was created by Chuck Lorre and Steven Molaro. The idea came from Jim Parsons, who plays adult Sheldon. In March 2017, Iain Armitage was cast as young Sheldon, and Zoe Perry as his mother, Mary Cooper. Zoe Perry is the real-life daughter of Laurie Metcalf, who plays Mary Cooper on The Big Bang Theory.

CBS ordered Young Sheldon in March 2017. Jon Favreau directed the first episode. The series follows 9-year-old Sheldon Cooper as he attends high school in East Texas. Jim Parsons narrates the series as the adult Sheldon. The show premiered on September 25, 2017. It was renewed for multiple seasons and ended on May 16, 2024. The final episode included a cameo from Jim Parsons and Mayim Bialik as their older characters.

Georgie & Mandy's First Marriage

In January 2024, it was announced that a spin-off of Young Sheldon would focus on Georgie Cooper and Mandy McAllister. This new series started in the 2024–25 TV season on CBS.

Stuart Fails to Save the Universe

In April 2023, a new spin-off of the original series was announced. In October 2024, it was shared that this third spin-off would feature Stuart Bloom, his girlfriend Denise, and geologist Bert Kibbler. Kevin Sussman, Lauren Lapkus, and Brian Posehn returned to play their roles. In March 2025, the show's title was announced as Stuart Fails to Save the Universe.

TV Special

On May 16, 2019, a TV special called Unraveling the Mystery: A Big Bang Farewell aired after the series finale. It was a behind-the-scenes look featuring Johnny Galecki and Kaley Cuoco.

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See also

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