Gamma World is a post-apocalyptic science fantasy role-playing game in which player characters explore Earth centuries after the collapse of civilization, searching for artifacts from the time before "The Great Upheaval". The game was originally designed by James M. Ward and Gary Jaquet, and first published by TSR in 1978. It borrows heavily from Ward's earlier role-playing game, Metamorphosis Alpha.

James Michael Ward III was an American game designer and fantasy author who worked for TSR, Inc. for more than 20 years, most notably on the role-playing game Dungeons & Dragons. He wrote various books relating to Dungeons & Dragons, including guidebooks such as Deities & Demigods, and novels including Pool of Radiance, based on the computer game of the same name.