A tiefling is a creature in the Dungeons & Dragons fantasy role-playing game. Tieflings are "planetouched"; that is, they are mortal creatures that have in their blood some otherworldly characteristics. Tieflings are descended from demons, devils and other creatures of pure evil alignment (including Evil deities); although their evil ancestor may be many generations removed, the taint still lingers. They are predisposed to Evil alignments though by no means are they always Evil.

The good-alignment-derived counterparts to tieflings are called aasimar.

In the Planescape campaign setting, tieflings are a common race available to player characters, though they are mistrusted and reviled by almost all other creatures across the planes.