Kodachrome is the brand name for a color reversal film introduced by Eastman Kodak in 1935. It was one of the first successful color materials and was used for both cinematography and still photography. For many years, Kodachrome was widely used for professional color photography, especially for images intended for publication in print media.

Because of its complex processing requirements, the film was initially exclusively sold process-paid in the United States: customers had to pay Kodak for the cost of development when they bought the film, and independent photography stores were prohibited from developing Kodachrome photos. To develop the film, customers had to mail film to Kodak, who mailed the developed photos back for no additional charge. In 1954, the U.S. Department of Justice found this practice to be an uncompetitive violation of antitrust law. Kodak entered into a consent decree - this required the company to offer Kodachrome film for sale with and without the development fee, as well as license Kodachrome development patents to independent photography stores. Nonetheless, the process-paid arrangement continued in other markets around the world.

Due to the growth and popularity of alternative photographic materials, its complex processing requirements, and the widespread transition to digital photography, Kodachrome lost market share. Its manufacture was discontinued in 2009, and processing ended in December 2010.

In early 2017, Kodak announced they were investigating the possibility of reintroducing Kodachrome, but later conceded that this was unlikely to happen.