Q, played by John de Lancie, is a character in the Star Trek mythology who appears in Star Trek: The Next Generation, Star Trek: Deep Space Nine and Star Trek: Voyager. The name "Q" is also shared by other members of the Q Continuum. Gene Roddenberry chose the letter "Q" for the character and species in honor of his friend, Janet Quarton.

Beginning with the pilot episode of Star Trek: The Next Generation, Q became a popular recurring character, in large part because of the comedic and dramatic chemistry between de Lancie and Patrick Stewart as Captain Jean-Luc Picard.