The X-Men franchise owned and produced by 20th Century Studios.

A band of mutants, outcast from the world yet sworn to protect the innocent, the X-Men movies inhabit a large cinematic universe of reasonable complexity. Separated from the mainstream Marvel Cinematic Universe thanks to its original ownership by 20th Century Fox, the X-Men Cinematic Universe has since come to overlap with the MCU as an alternate timeline. For the most part, however, these movies remain their own, messy world, one that can be enjoyed outside the MCU.

Because X-Men: Days of Future Past is concerned with time travel and changing timelines, the events of the first three X-Men movies and X-Men Origins: Wolverine have been negated to a degree. This means that following a chronological order won't make much sense. You are recommended to instead watch the X-Men movies by order of release. If you're determined to watch them by timeline, however, see below.

Included in this list is the television show Legion. Despite coming out at the same time as the movies, as well as attempts to have some of the actors appear in the show, Legion never quite crossed over with the films, nor do the events of the films have an effect on Legion. It is included under Release Order only.

 In-Universe Chronological Order
Release Order