Traveller  is set in the distant future—over three thousand years removed from our own time. Interstellar travel is facilitated, and limited, by the use of a technology called the jump drive . Jump drives are capable of propelling a starcraft between one to six parsecs, depending on the individual drive's specifications. Regardless of the distance of a jump, the duration required for the trip is approximately one week. Communications are limited to the speed of travel; there is no "sub-space" or other form of FTL information transfer. This leads to a central principle that the restraint on the speed of information leads to decentralization and the vestment of significant power in the hands of local officials.

The primary galactic society in Traveller is the Third Imperium, a vast, human-dominated feudalistic union of over eleven thousand worlds. The Imperium is the most powerful interstellar polity, but it is surrounded on all sides by potentially hostile neighbors. Local nobility operate largely free from oversight, restricted by convention, feudal obligations, and the fear of being caught.

Traveller is grand space opera with untold number of alien species and exotic locales.