Tempus fugit is a Latin expression meaning "time flees", more commonly translated as "time flies". It is frequently used as an inscription on clocks. The expression was first used in the verse Georgica written by Roman poet Virgil: Sed fugit interea fugit irreparabile tempus, which means, "But it flees in the meantime: irretrievable time flees".

"Tempus Fugit" is the seventeenth episode of the fourth season of The X-Files. While celebrating Scully's birthday, Mulder learns of Max Fenig's death in a plane crash. What the agents soon discover is that the circumstances surrounding the crash may have been alien.