The Marvel Cinematic Universe (MCU) is an American media franchise and shared universe centered on a series of superhero films produced by Marvel Studios. The films are based on characters that appear in American comic books published by Marvel Comics. The franchise also includes television series, short films, digital series, and literature. The shared universe, much like the original Marvel Universe in comic books, was established by crossing over common plot elements, settings, cast, and characters.

A shared universe or shared world is a fictional universe from a set of creative works where one or more writers independently contribute works that can stand alone but fits into the joint development of the storyline, characters, or world of the overall project. It is common in genres like science fiction. It differs from collaborative writing in which multiple artists are working together on the same work and from crossovers where the works and characters are independent except for a single meeting.