X-Men First Class came the earliest. It stars James McAvoy as Charles Xavier and showcases events from the 1960s.
Days of Future Past takes place in 1973. However, much of the plot of this X-Men movie deals with the future.
Wolverine begins in 1845 when he first discovers and harnesses his new powers. However, most of the events in the movie occur in 1979.
Apocalypse focuses on the X-Men fighting against their mutant enemy, En Sabah Nur, in the 1980s.
Dark Phoenix happened in 1992. The movie, featuring Sophie Turner as Jean Gray, was one of the films to showcase the lives of the young cast.
X-Men was the first movie from the franchise to release in theatres. However, it’s the sixth movie in the overall timeline.
X2 was the franchise’s first sequel. All the events in the movie happened in 2003. The X-Men team up to rescue Professor Xavier from anti-mutant Colonel William Stryker.
The Last Stand was the final film in the original series. Jean Gray takes on her alternate persona, Phoenix, for the first time in the movie series.
Hugh Jackman’s Wolverine finds himself grieving the loss of Jean Gray when he arrives in Japan to reconnect with an old friend, he saved years ago.
Ryan Reynolds’ Deadpool is the most different movie in the X-Men and the Marvel franchise.
The New Mutants, set in 2017, introduces five new young mutants. However, you can skip this one as the events in the story do not affect the others.
Deadpool 2, set in 2018, features a cameo from the young X-Men. Deadpool travels back to X-Men Origins: Wolverine.
Logan takes place in the future in 2029. When the mutants are almost extinct, a mutant child named Laura comes to Wolverine for help. The movie ties the entire series quite nicely.