Bill & Ted is an American science fiction comedy franchise created by Chris Matheson and Ed Solomon. It features William "Bill" S. Preston Esq. and Ted "Theodore" Logan, portrayed by Alex Winter and Keanu Reeves, respectively, two metalhead slacker friends who travel through time and beyond while trying to fulfill their destiny to establish a utopian society in the universe with their music. The series spans a film trilogy: Bill & Ted's Excellent Adventure (1989), Bill & Ted's Bogus Journey (1991), and Bill & Ted Face the Music (2020). The series has been mainly produced by Scott Kroopf.

There have been numerous spin-offs, including an animated television series (with Winter and Reeves reprising their roles), a live-action television series in 1992, video games and comic books. Originally released by Orion Pictures and produced by Nelson Entertainment and Interscope Communications, ownership moved to Metro-Goldwyn-Mayer following the purchase of PolyGram Filmed Entertainment's pre-April 1996 library in October 1998, and MGM has been the main licensee and distributor since. The series has grossed $85 million and received generally positive reviews from critics.

The series follows the pair of William "Bill" S. Preston Esq. (Alex Winter) and Ted "Theodore" Logan (Keanu Reeves), initially two teenagers living in San Dimas, California in 1988. They want to make their rock band "Wyld Stallyns" successful, but their ambitions and lackadaisical attitudes leave them close to flunking out of high school and threatening to split the band up forever. Unbeknownst to them, their music will form the basis of a utopian society in the future. The leaders of this society send Rufus (George Carlin) to help Bill & Ted pass school and assure the future with the aid of a time machine, which appears as a phone booth. Later films focus on attempts by others to break up Bill & Ted so that their music will never lead to a utopian future.

Excellent Adventure introduces Bill and Ted who are trying to write a history report. Rufus, a guide from the year 2688, arrives to provide them the time machine which allows them to travel back in time and meet historical figures in order to learn about key historical events. If Bill and Ted fail to pass, their teacher will have to flunk them and Ted's father will transfer him to an Alaskan military high school, which will lead to Wyld Stallyns never forming, in turn destroying a Utopian future built around their music.

In Bogus Journey, Chuck De Nomolos, a resident of the utopia, is sick of it and sends a pair of Bill & Ted robot doubles back into the past to kill Bill and Ted and make a future based on his ideals. Bill & Ted are killed, face the Grim Reaper, and manage to beat him at several games. This gives them the opportunity to find allies to stop their robot doubles and De Nomolos before an upcoming Battle of the Bands where they must also rescue the princesses to whom they are engaged and start their musical careers.

Bill and Ted are now middle-aged parents, yet to realize the music that the future Utopian society will follow. They are warned by the Great Leader and Rufus's daughter Kelly from the future that they have only a short time in their present to create the great song or reality will collapse. Bill and Ted decide to travel to their future to try to find their song but are hunted by a time-travelling robot. Kelly warns their teenage daughters, Billie and Thea, about their plight, and the two go off into the past to help create a band to make the great song for their fathers in time.

Shortly before the release of Face the Music, Winter and Reeves discussed the possibility of a fourth Bill & Ted movie, the latter telling Rachel Smith of Entertainment Tonight that it would be "up to the fans". When asked in an interview with DiscussingFilm in August 2020 if the characters of Billie and Thea could result in a sequel or spin-off film, writer Ed Solomon stated, "It wasn't when we were first writing it, but as we saw Brigette and Samara inhabit these roles, I thought for sure if there was interest and people wanted to carry this forward, the Bill & Ted spirit, I would absolutely let those characters carry it forward. I think we've finished with the Alex and Keanu Bill & Ted story. I think it's done, but if people were interested in a Billie & Thea continuation, I think it'd be cool."

The first season was produced by Hanna-Barbera and ran for 13 episodes on CBS in 1990, featured the voices of Carlin, Winter and Reeves returning to their roles in the film. A second season of eight episodes ran on Fox Kids and was produced by DIC Entertainment, with none of the original cast.