Ultima IV: Quest of the Avatar, first released in 1985 for the Apple II, is the fourth in the series of Ultima role-playing video games. It is the first in the "Age of Enlightenment" trilogy, shifting the series from the hack and slash, dungeon crawl gameplay of its "Age of Darkness" predecessors towards an ethically-nuanced, story-driven approach. Ultima IV has a much larger game world than its predecessors, with an over world map sixteen times the size of Ultima III and puzzle-filled dungeon rooms to explore. Ultima IV further improves the franchise with dialog improvements, new means of travel and exploration, and world interactivity.

In 1996 Computer Gaming World named Ultima IV as #2 on its Best Games of All Time list on the PC. Designer Richard Garriott considers this game to be among his favorites from the Ultima series.