X-Men

The X-Men are a fictional team of superheroes appearing in American comic books published by Marvel Comics. Created by artist/co-plotter Jack Kirby and writer/editor Stan Lee, the characters first appeared in The X-Men #1 (September 1963) and formed one of the most recognizable and successful franchises of Marvel Comics, appearing in numerous books, television shows, films, and video games.

In the Marvel Universe, mutants are humans who are born with natural superhuman abilities, and most normal humans fear and hate them. The X-Men are a paramilitary group of mutants that fights for peace and equality between normal humans and mutants. They are led by Charles Xavier, also known as Professor X, a powerful telepath. Professor X runs a school for mutant children out of his mansion in Westchester, New York, which secretly is also the headquarters of the X-Men. The X-Men's archenemy is Magneto, a mutant with magnetic abilities who leads a mutant supremacist group known as the Brotherhood of Mutants.

The series' creator and fans have suspected that Marvel Comics copied the basic concept of Doom Patrol from DC Comics to create the X-Men, which debuted a few months later, but other fans also speculate that they share similarities with another Marvel superhero team, the Fantastic Four.

Original members
Notation:
 * Characters in bold are members of the team as of the present time.
 * A slash (/) between names indicates codenames of one character in chronological order.
 * Characters listed are set in the Earth-616 continuity except when noted.

New Mutants graduate X-Men
In 1986, the New Mutants briefly graduated to become the X-Men in Uncanny X-Men Annual #10.

Muir Island X-Men
In 1989, in the wake of the X-Men's "death" during "The Fall of the Mutants", Banshee assembled a team of X-Men on Muir Island in Uncanny X-Men #254 to #255.

Phalanx invasion X-Men
In 1994, to oppose the threat of the techno-organic alien Phalanx, a team of X-Men was quickly banded together in Uncanny X-Men #316.

Mannite rescue X-Men
In 1999, after Professor X disbanded the X-Men in an attempt to expose a Skrull impostor in their ranks, Cyclops and Jean Grey formed a team to help the Mannites in Astonishing X-Men, vol. 2 #1.

Genoshan assault X-Men
In 2001, Jean Grey recruited a team in Uncanny X-Men #392 in order to rescue Professor X from Magneto.

Street team X-Men
In 2004, a team was formed by Cyclops in the wake of Xorn's rampage through Manhattan, New York in New X-Men #149 and #150.

X-Men in training
Mutants to be trained as a junior team of X-Men.

X-Force
In 2008, the X-Men's strike team was formed by Cyclops in Uncanny X-Men #493, with Wolverine serving as the field leader. The team took on missions which required responses too violent or controversial for the X-Men to deal with directly. When Cyclops disbanded the team, Wolverine assembled a new team.

X-Club
In 2009, Beast gathered a team in Uncanny X-Men #504 to attempt to deal with the mutant birth crisis, and reverse the effects of M-Day. The team lasted until 2012.

Time-displaced X-Men
Headlined All-New X-Men from 2012 to 2017 and X-Men Blue from 2017 to 2018.

London X-Men
In 2017, a team was formed to help Charles Xavier against the Shadow King in Astonishing X-Men, vol. 4.

Secret X-Men
A team formed in 2022, the Secret X-Men are tasked with saving the daughter of Xavier and Lilandra, Empress Xandra of the Shi'ar Empire. Their debut was in Secret X-Men #1.

Unofficial
The teams who have used the name of the X-Men without the permission of the official X-Men. They were either opposed to the X-Men altogether, or used the name to promote themselves to the public.

Cerebro's X-Men
Main article: Cerebro's X-Men

Nanotechnology imposter team formed in 1998 by a sentient Cerebro posing as Professor X.

Great Lakes X-Men
In 2005, served a cease and desist for his team's use of the Avengers name, Mr. Immortal reorganized the Great Lakes Avengers into a team of unofficial X-Men in G.L.A. #4. They have since changed their name to first Great Lakes Champions and then Great Lakes Initiative.

Norman Osborn's X-Men
In 2009, a team of X-Men assembled by Norman Osborn during the "Utopia" storyline as part of the overarching "Dark Reign" event.

X-Men Green
Rogue team formed in 2021 to combat environmental destruction at all costs.