Traveller is a science fiction role-playing game first published in 1977 by Game Designers' Workshop. Marc Miller designed Traveller with help from Frank Chadwick, John Harshman, and Loren Wiseman. Editions were published for GURPS, d20, and other role-playing game systems. From its origin and in the currently published systems, the game relied upon six-sided dice for random elements. Traveller has been featured in a few novels and at least two video games.

Marc William Miller is a wargame and role-playing game designer and author.