The Dark Mark is the personal sign of the dark wizard Lord Voldemort and his inner circle of followers, known as the Death Eaters. Although variations of the symbol appear in adaptions and in fan-based artwork, the imagery is always the same; a skull with a serpent protruding from its mouth.

The mark may be conjured using the incantation "morsmordre" (pronounced mors-mor-druh, from Latin "to bite death"), and was sent into the sky by the Death Eaters whenever they committed murder and wanted to make a statement. The symbol was also tattooed on the inner left forearm of each Death Eater. If they ever felt the mark burn their skin, it meant they were to go immediately to Lord Voldemort's side, for he had requested their presence.