---
title: "The Big Bang Theory"
chunk: 1/11
source: "https://en.wikipedia.org/wiki/The_Big_Bang_Theory"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:04:29.021226+00:00"
instance: "kb-cron"
---

The Big Bang Theory is an American television sitcom created by Chuck Lorre and Bill Prady for CBS. It aired from September 24, 2007, to May 16, 2019, running for 12 seasons and 279 episodes.
The show originally centered on five characters living in Pasadena, California: Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons), both physicists at the California Institute of Technology, who share an apartment; Penny (Kaley Cuoco), a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon's similarly geeky and socially awkward friends and coworkers, aerospace engineer Howard Wolowitz (Simon Helberg) and astrophysicist Raj Koothrappali (Kunal Nayyar). Over time, supporting characters were promoted to starring roles, including neuroscientist Amy Farrah Fowler (Mayim Bialik), microbiologist Bernadette Rostenkowski (Melissa Rauch), and comic book store owner Stuart Bloom (Kevin Sussman).
The series was filmed in front of a live audience and produced by Chuck Lorre Productions, with Warner Bros. Television handling distribution. While the first season received mixed reviews, critical reception improved in subsequent seasons. Seven seasons ranked within the top ten of the final-season ratings, and the series reached the No. 1 spot in its eleventh season. It was nominated for the Emmy Award for Outstanding Comedy Series from 2011 to 2014 and won the Emmy Award for Outstanding Lead Actor in a Comedy Series four times for Parsons, totaling seven Emmy Awards from 46 nominations. Parsons also won the Golden Globe for Best Actor in a Television Comedy Series in 2011.
The success of The Big Bang Theory launched a multimedia franchise. A prequel series focusing on Parsons' character Sheldon Cooper, Young Sheldon, aired from 2017 to 2024, with Parsons narrating as the adult Sheldon. The third series in the franchise, a sequel to Young Sheldon titled Georgie & Mandy's First Marriage, premiered in October 2024 and follows Sheldon's older brother, Georgie, and his wife, Mandy. A fourth series, following Stuart Bloom and his girlfriend Denise, along with geologist Bert Kibbler titled Stuart Fails to Save the Universe, is currently in development for HBO Max.

== Plot ==

=== Seasons 1–4 ===
The series centers on the evolving relationships between socially awkward physicists Leonard Hofstadter and Sheldon Cooper, their neighbor Penny, and their friends Howard Wolowitz and Raj Koothrappali. The central romantic storyline begins when Leonard becomes immediately attracted to Penny, an aspiring actress and waitress who moves in across the hall. Throughout the first season, Leonard attempts various schemes to win Penny's affection while she dates a series of conventionally attractive but intellectually incompatible men.
The group's friendship dynamics are established as they navigate their shared interests in science fiction, comic books, and video games, often clashing with their limited social skills. Sheldon's rigid personality and numerous quirks create ongoing conflicts with his roommate Leonard, while Howard's inappropriate behavior toward women and his unhealthy relationship with his mother provide additional comedic tension. Raj's selective mutism around women becomes a recurring obstacle to his romantic pursuits.
Leonard and Penny's relationship experiences its first major development when Leonard returns from a three-month Arctic expedition in the season three premiere, leading to their first serious romantic relationship. However, the relationship becomes strained when Leonard prematurely declares his love for Penny, who cannot reciprocate the sentiment. Their subsequent breakup leads Leonard to pursue a relationship with Raj's sister Priya during much of season four, creating tension within the friend group and jealousy from Penny.

=== Seasons 5–8 ===
The series expands its core cast with the introduction of Amy Farrah Fowler, a neurobiologist matched with Sheldon through online dating, and Bernadette Rostenkowski, a microbiologist who begins dating Howard. These additions create new relationship dynamics and storylines while allowing for character development among the original cast members.
Sheldon and Amy's relationship develops slowly from a purely intellectual connection to a romantic partnership, with Sheldon gradually overcoming his aversion to physical contact and emotional intimacy. Their relationship is marked by formal agreements and scientific approaches to romance, reflecting both characters' analytical personalities.
Howard's relationship with Bernadette leads to significant character growth as he learns to become more mature and less dependent on his mother. Their relationship culminates in marriage during the fifth season finale, coinciding with Howard's departure for a space mission to the International Space Station.
Leonard and Penny reconcile and resume their romantic relationship, though it faces various challenges including Leonard's insecurities and Penny's career struggles. Leonard's multiple attempts to propose marriage are initially rejected by Penny, who feels unprepared for such commitment. The relationship dynamics continue to evolve as both characters mature and better understand each other's needs and perspectives.

=== Seasons 9–12 ===
The final seasons focus on the progression of established relationships toward marriage and long-term commitment. Leonard and Penny finally marry in the season nine premiere, though their wedding is preceded by Leonard's confession of kissing a co-worker during his Arctic expedition. Despite this obstacle, they successfully navigate married life and eventually move into their own apartment when Sheldon relocates.
Sheldon and Amy's relationship reaches several major milestones, including their first sexual encounter on Amy's birthday and eventual cohabitation. After a temporary breakup caused by Sheldon's fear of commitment, they reunite and become engaged. Their wedding in the season eleven finale represents the culmination of Sheldon's character development from an emotionally closed individual to someone capable of love and partnership.
The series concludes with the characters achieving personal and professional fulfillment. The final episode reveals Penny's pregnancy while focusing on Sheldon and Amy receiving the Nobel Prize in Physics, bringing the characters' scientific careers full circle while emphasizing the importance of their personal relationships and friendships that have sustained them throughout the series.

== Cast and characters ==