Ultima III: Exodus is the third game in the series of Ultima role-playing video games. Exodus is also the name of the game's principal antagonist. It is the final installment in the "Age of Darkness" trilogy. Released in 1983, it was the first Ultima game published by Origin Systems. Originally developed for the Apple II, Exodus was eventually ported to 13 other platforms, including a NES/Famicom remake.

Ultima III revolves around Exodus, the spawn of Mondain and Minax (from Ultima I and Ultima II, respectively), threatening the world of Sosaria. The player character travels to Sosaria to defeat Exodus and restore the world to peace. Ultima III hosts further advances in graphics, particularly in animation, adds a musical score, and increases the player's options in gameplay with a larger party and more interactivity with the game world.

Ultima III was followed by Ultima IV: Quest of the Avatar in 1985.