Ringworld is a Hugo and Nebula award-winning 1970 science fiction novel by Larry Niven, set in his Known Space universe. The work is widely considered one of the classics of science fiction literature. It is followed by three sequels, and it ties in to numerous other books in the Known Space universe.

The Ringworld science fiction role-playing game was published by Chaosium in 1984, using the Basic Role-Playing system for its rules and Larry Niven's Ringworld novels as a setting.