Marvel Cinematic Universe: Phase One

Phase One of the Marvel Cinematic Universe (MCU) is a group of American superhero films produced by Marvel Studios based on characters that appear in publications by Marvel Comics. The MCU is the shared universe in which all of the films are set. Marvel previously licensed the film rights for some characters to other studios, before Marvel Studios was formed to produce their own feature films. Following the success of Iron Man, which began Phase One in May 2008, the studio moved forward with a plan to have individual superhero films culminate in a crossover film, The Avengers, which ended the phase in May 2012. Phases One, Two, and Three make up "The Infinity Saga" storyline.

Kevin Feige produced every film in the phase, with Avi Arad also producing Iron Man and The Incredible Hulk (2008), and Gale Anne Hurd also producing the latter. The films star Robert Downey Jr. as Tony Stark / Iron Man in Iron Man and Iron Man 2 (2010), Edward Norton as Bruce Banner / Hulk in The Incredible Hulk, Chris Hemsworth as Thor in Thor (2011), and Chris Evans as Steve Rogers / Captain America in Captain America: The First Avenger (2011). All returned to star in The Avengers except for Norton, who was replaced by Mark Ruffalo. Samuel L. Jackson has the most appearances in the phase, starring or making cameo appearances as Nick Fury in five films. Paramount Pictures distributed the films except for The Incredible Hulk, which was released by Universal Pictures, and The Avengers, which was released by Walt Disney Studios Motion Pictures. The films grossed over US$3.8 billion at the global box office, received generally positive critical and public responses, and were credited with establishing a foundation for the success of later phases.

In addition to the feature films, the phase also includes three short films that Marvel Studios created for their Marvel One-Shots program—The Consultant, A Funny Thing Happened on the Way to Thor's Hammer, and Item 47—to expand the MCU. Each feature film also received tie-in comic books and video games.