NYX is a limited series of comic books by Marvel Comics, consisting of seven issues, published between 2003 and 2005. It is written by Joe Quesada with art by Joshua Middleton (issues #1–4) and Rob Teranishi (issues #5–7). NYX stands for District X, New York City.

The series features homeless teenage mutants in New York City: time-freezing Kiden, shape-shifting Tatiana, body-shifting Bobby, his mysterious brother Lil Bro, the female clone of Wolverine (X-23), and Cameron, a woman with no powers. The third issue of the series featured the first comic book appearance of X-23, a character created on the X-Men: Evolution cartoon. Although the series was cancelled in 2005, a sequel 6-issue miniseries titled NYX: No Way Home was released in 2009.

A second volume was published from July 2024 to April 2025 as part of the X-Men: From the Ashes event which relaunches the X-Men line. The series focuses on former X-Men students and Kamala Khan as they adapt to life in New York City in the post-Krakoan Age, where mutants are hated and feared even more due to the actions of Orchis. Laura Kinney (formerly X-23) and Kiden Nixon are the only returning characters.

In 2001, writer Brian Wood developed a concept of the series for Marvel with artist David Choe that was to launch Marvel's MAX imprint. The ongoing series, focusing on the characters and how their powers affect their lives, friends and family, was to star Gambit, Rogue, and Jubilee, as well as Angie and Purge, two new characters Wood had created for the series. After Marvel aborted the project, deeming it not suitable for their audience, Wood used parts of this concept for his series Demo.

The series ended up being developed and written by Joe Quesada with art by Joshua Middleton (issues #1–4) and Rob Teranishi (issues #5–7). Quesada told Dana Jennings of The New York Times that "almost everything you see in NYX is based on something I know or have seen firsthand". Jennings highlighted that Quesada's "idea for NYX came the way lots of New York writers used to get their ideas, outside a saloon":

''I was at the Ace Bar in Alphabet City,'' he says, ''and I saw these 15-year-old squatters eating discarded bread.'' The scene haunted him, and evolved into NYX. ''With comic books, you look at real-life situations and try to find the right metaphor,'' Mr. Quesada says. ''You ask yourself, 'What if we took the world of the X-Men and shrunk it down?' What if your concern was, 'When am I going to eat next,' even if you do have superpowers?''

NYX was planned as an ongoing series, but later was shortened to a miniseries. Throughout the entire publication, there were often long delays between issues because Quesada had always been late with scripts. The first five issues of the series were reprinted in two Marvel Must Haves issues in the summer of 2005, before the sixth issue was released in July. The seventh and last issue was released in September 2005.

A second series of NYX was planned for release in 2007, but never materialized.