The Big Bang Theory franchise started on CBS in 2007 with a multi-camera sitcom about Caltech physicists Leonard Hofstadter and Sheldon Cooper, plus Penny, the aspiring actress who moved in across the hall. Chuck Lorre and Bill Prady built the show around comic book stores and Star Trek arguments, and it ran for 12 seasons and 279 episodes before wrapping in May 2019. The franchise kept going anyway. Young Sheldon went back to 1989 East Texas for seven seasons of Sheldon's childhood, with Jim Parsons narrating. Georgie & Mandy's First Marriage followed Sheldon's older brother into an early marriage and started its third season on CBS in October 2026. Stuart Fails to Save the Universe then pushed the timeline forward on HBO Max, sending comic book store owner Stuart Bloom through a multiverse full of alternate versions of the original cast. This page covers all four shows along with the in-universe timeline, the recommended watch order, the actors who connect the series, and the continuity problems that come from telling one family's story from two directions.
The Big Bang Theory premiered on CBS on September 24, 2007. Leonard Hofstadter (Johnny Galecki) and Sheldon Cooper (Jim Parsons) are Caltech physicists sharing an apartment in Pasadena, and their usual crowd includes aerospace engineer Howard Wolowitz (Simon Helberg) and astrophysicist Raj Koothrappali (Kunal Nayyar). Penny (Kaley Cuoco) moves in across the hall in the pilot, and Leonard's crush on her drives most of the early seasons.
The version that aired was a retool. An unaired first pilot featured a character named Katie instead of Penny, and CBS sent the show back for changes before it went to series. The retooled cast stuck, and the show stayed on the network for 12 seasons. Jim Parsons won four Emmy Awards for Outstanding Lead Actor in a Comedy Series for playing Sheldon.
I know a lot of people hated the show and felt that it was making fun of nerd culture, and I suppose to some degree that is true. There were extremes, but there were also depictions that weren't as extreme as the core cast. I found it to be funny because I could see myself in the characters, maybe not as extreme as them, but definitely part of me was in there.
Mayim Bialik first appeared as neuroscientist Amy Farrah Fowler in the season 3 finale, and Melissa Rauch arrived as microbiologist Bernadette Rostenkowski during season 3 as well. Both became series regulars in season 4, which shifted the show from a story about four guys and a neighbor into an ensemble about three couples. Howard and Bernadette married in season 5, Leonard and Penny married in season 9, and Sheldon and Amy married in the season 11 finale.
Kevin Sussman first showed up as Stuart Bloom, the owner of the comic book store, in season 2. Stuart started as a guy behind a counter and slowly turned into a semi-permanent member of the group, at one point living with Howard's mother. John Ross Bowie played Barry Kripke, Sheldon's rival at Caltech, across 11 seasons. Brian Posehn played geologist Bert Kibbler, and Lauren Lapkus played Denise, who worked at Stuart's store and became his girlfriend in the final seasons. Those four are the core cast of Stuart Fails to Save the Universe.
Other recurring faces include Laurie Metcalf as Sheldon's mother Mary Cooper, Christine Baranski as Leonard's mother Beverly Hofstadter, Wil Wheaton as a fictionalized version of himself, and Bob Newhart as Professor Proton, a role that earned Newhart his first Emmy win.
The Big Bang Theory ended because Jim Parsons decided not to continue past season 12, and the cast and producers chose to end the show rather than go on without Sheldon. The series finale aired as a one-hour event on May 16, 2019. Sheldon and Amy win the Nobel Prize in Physics for their work on super-asymmetry, Leonard and Penny learn they are expecting a baby, and the apartment building elevator that had been broken since before the pilot finally works again. Sheldon's Nobel acceptance speech, where he drops his prepared remarks to thank his friends, is the scene most people remember from the finale.
Young Sheldon premiered on CBS on September 25, 2017, while The Big Bang Theory was still airing, and ran for seven seasons and 141 episodes before ending on May 16, 2024. Chuck Lorre and Steven Molaro created the show as a single-camera prequel with no studio audience. Iain Armitage plays nine-year-old Sheldon Cooper starting high school in Medford, Texas in 1989, and Jim Parsons narrates every episode as adult Sheldon.
Zoe Perry plays Mary Cooper, the same character her real-life mother Laurie Metcalf played on The Big Bang Theory. Lance Barber plays George Cooper Sr., Montana Jordan plays Sheldon's older brother Georgie, and Raegan Revord plays his twin sister Missy. Annie Potts plays Meemaw, Sheldon's grandmother Connie Tucker, and Wallace Shawn plays Dr. John Sturgis, Sheldon's professor and Meemaw's boyfriend. Emily Osment joined in later seasons as Mandy McAllister, an older woman Georgie gets pregnant, which set up the next spinoff.
George Cooper Sr. dies of a heart attack in season 7 of Young Sheldon. The death was never a twist, since The Big Bang Theory established years earlier that Sheldon's father died when Sheldon was 14. Young Sheldon spent most of its final season building toward it, and the episode titled "Funeral" deals with the Cooper family burying George. Lance Barber's version of the character is much warmer than the father adult Sheldon described in The Big Bang Theory, which made the death land harder for viewers who only knew him through Sheldon's complaints.
The Young Sheldon series finale, "Memoir," sends 14-year-old Sheldon off to Caltech and brings Jim Parsons and Mayim Bialik onscreen as adult Sheldon and Amy. The finale reveals that the narration across all seven seasons is Sheldon writing his memoir, with Amy and their children in the house around him. That framing also gave the writers an in-universe explanation for every detail that didn't line up with The Big Bang Theory.
Georgie & Mandy's First Marriage premiered on CBS on October 17, 2024. It picks up in 1994 right after Young Sheldon, with Georgie Cooper (Montana Jordan) and Mandy McAllister (Emily Osment) raising their baby daughter CeCe while living with Mandy's parents. The show went back to the multi-camera, live studio audience format of The Big Bang Theory instead of the single-camera style of Young Sheldon.
Will Sasso plays Mandy's father Jim McAllister, whose tire shop Georgie works at, and Rachel Bay Jones plays her mother Audrey. Dougie Baldwin plays Mandy's brother Connor, and Jessie Prez plays Georgie's coworker Ruben Alvarez. Zoe Perry continues as Mary Cooper. Season 2 ended with Georgie discovering that his mother was dating Fred Fagenbacher (Matt Letscher), his rival in the tire business, and cutting Mary off from her granddaughter.
Season 3 of Georgie & Mandy's First Marriage premiered on October 8, 2026 with "Feminine Wiles and Some Tire Thing in Lubbock," where the McAllisters side against Georgie in his fight with Mary. The title of the show still hangs over everything, since "first marriage" implies a second one. Jerry O'Connell played adult Georgie in season 12 of The Big Bang Theory, already running his own chain of tire stores, so the business side of his future is locked in even if the marriage isn't.
Stuart Fails to Save the Universe premiered on HBO Max on July 23, 2026, and its 10-episode first season ran weekly through September 24, 2026. Chuck Lorre, Bill Prady, and Zak Penn co-created the series, which was first announced as being in development in 2023. It is the first Big Bang Theory spinoff set after the original series, and the first one built around characters who were never part of the main group.
Stuart Bloom (Kevin Sussman) breaks a quantum device built by Sheldon and Leonard, and the accident sets off a multiverse Armageddon. Stuart has to fix it with help from Denise (Lauren Lapkus), Bert Kibbler (Brian Posehn), and Barry Kripke (John Ross Bowie), and the four of them bounce between alternate realities where familiar Big Bang Theory characters live very different lives. Danny Elfman wrote the theme music. HBO Max renewed Stuart Fails to Save the Universe for season 2 only four episodes into its first season.
I often write about how I wish series were longer, but for this, I wish the episode length was longer. Half of the episodes were under 20 minutes. Even if this was airing on CBS, the show would still be around 21 minutes, and this is HBO Max, so there's no set time limit. I hope the second season's episodes are longer.
Kunal Nayyar returns in the premiere as an alternate Raj Koothrappali, a long-haired prisoner in a post-apocalyptic world ruled by Barry Kripke, and the episode ends with Kripke killing him. In episode 2, Kaley Cuoco plays an alternate Penny who never met Leonard and leads a resistance against an AI regime, with her ex Zack (Brian Thomas Smith) at her side. Melissa Rauch as Bernadette and Mayim Bialik as Amy both turned up within the first four episodes. Penn & Teller also appear running a magic show in the premiere, and Teller previously played Amy's father on The Big Bang Theory.
Jim Parsons and Johnny Galecki did not appear as Sheldon and Leonard during the early run, even though the whole plot hinges on their device. Chuck Lorre said the cameos came down to which actors were available and what each story needed.
In story order, Young Sheldon comes first, covering 1989 to 1994 as Sheldon goes from age nine to 14 and leaves for Caltech. Georgie & Mandy's First Marriage starts in 1994 and runs alongside Sheldon's early college years offscreen. The Big Bang Theory jumps to 2007 and runs in real time through 2019, ending with the Nobel Prize ceremony in Stockholm. Stuart Fails to Save the Universe takes place after The Big Bang Theory finale, with the multiverse premise opening up alternate timelines that branch off from the main one.
Release order is The Big Bang Theory (2007), Young Sheldon (2017), Georgie & Mandy's First Marriage (2024), and Stuart Fails to Save the Universe (2026). Chronological order swaps the first two, starting with Young Sheldon and then Georgie & Mandy's First Marriage before The Big Bang Theory and Stuart Fails to Save the Universe.
Release order works better for a first watch. Young Sheldon is written with the assumption that viewers already know adult Sheldon, so a lot of the narration jokes and foreshadowing only work with The Big Bang Theory in the background. Stuart Fails to Save the Universe leans even harder on that knowledge, since its whole cast comes from the original show's supporting players and most of its surprises are alternate versions of characters from the mothership.
Gaming was part of the furniture on The Big Bang Theory from the start. The guys kept a standing Halo night in the early seasons, and the Halo franchise shows up regularly in the background of the apartment scenes. In season 2's "The Barbarian Sublimation," Penny gets hooked on the MMO Age of Conan, and in season 4's "The Zarnecki Incursion," Sheldon's World of Warcraft account gets hacked and his gear stolen, which sends the group on a real-world trip to confront the thief.
The show also gave the internet rock-paper-scissors-lizard-Spock, a game created by Sam Kass and Karen Bryla that Sheldon explains in season 2's "The Lizard-Spock Expansion." Mystic Warlords of Ka'a, the fictional card game the group plays, became popular enough that fans made their own versions.
Comic books were just as central. Stan Lee guest starred as himself in season 3's "The Excelsior Acquisition," a big moment for the Marvel side of the show's references. On the DC side, Sheldon's go-to costume is The Flash, and season 4's "The Justice League Recombination" has the whole group dressing as the Justice League for a New Year's Eve costume contest. Star Wars got its own episode in season 9's "The Opening Night Excitation," built around the premiere of The Force Awakens, and Mark Hamill officiated Sheldon and Amy's wedding in the season 11 finale, "The Bow Tie Asymmetry."
Jim Parsons is the obvious connection, playing Sheldon on The Big Bang Theory, narrating all of Young Sheldon, and appearing onscreen in the Young Sheldon finale. Mayim Bialik also crossed over for that finale. The Mary Cooper casting is the best piece of trivia in the franchise, since Zoe Perry played the younger version of the character her mother Laurie Metcalf originated. Teller has played three different roles across the franchise, as Amy's father Larry Fowler on The Big Bang Theory, Pus opposite Penn Jillette's Acne in the Young Sheldon season 5 finale, and himself in Stuart Fails to Save the Universe.
Telling Sheldon's childhood after a decade of adult Sheldon describing it created problems. The Big Bang Theory painted George Cooper Sr. as a distant father Sheldon had little good to say about, while Young Sheldon's version is flawed but clearly loves his family. Smaller details about Missy, Meemaw, and Georgie also drifted between the two shows.
The Young Sheldon finale handled this by revealing that the narration was Sheldon writing his memoir as an adult. That makes adult Sheldon an unreliable narrator in both directions, so the bitter version of his childhood on The Big Bang Theory and the warmer version on Young Sheldon can both be read as Sheldon's own take at different points in his life. Georgie & Mandy's First Marriage inherits the same issue, since adult Georgie on The Big Bang Theory was estranged from Sheldon in ways the prequel shows haven't fully explained yet.
The Big Bang Theory ran for 12 seasons and 279 episodes on CBS from September 2007 to May 2019.
Jim Parsons decided not to return after season 12, and the producers and cast chose to end the series instead of continuing without Sheldon Cooper.
Yes. Stuart Fails to Save the Universe is an official spinoff from Chuck Lorre Productions, co-created by Chuck Lorre and Bill Prady with Zak Penn, and it is set after The Big Bang Theory finale with Kevin Sussman returning as Stuart Bloom.
Yes. HBO Max renewed Stuart Fails to Save the Universe for season 2 in August 2026, four episodes into its first season.
Jim Parsons narrates every episode of Young Sheldon as adult Sheldon and appears onscreen with Mayim Bialik in the series finale, "Memoir."
Yes. Zoe Perry, who plays Mary Cooper on Young Sheldon and Georgie & Mandy's First Marriage, is the daughter of Laurie Metcalf, who played Mary Cooper on The Big Bang Theory.
Georgie & Mandy's First Marriage season 3 premiered on CBS on October 8, 2026.
Release order works best for a first watch: The Big Bang Theory, Young Sheldon, Georgie & Mandy's First Marriage, then Stuart Fails to Save the Universe.