Worf, son of Mogh is a fictional character in the Star Trek franchise, portrayed by actor Michael Dorn. He appears in the television series Star Trek: The Next Generation (TNG), seasons four through seven of Star Trek: Deep Space Nine (DS9) and the third and final season of Star Trek: Picard, as well as the feature films Star Trek Generations (1994), Star Trek: First Contact (1996), Star Trek: Insurrection (1998), and Star Trek: Nemesis (2002).

Worf is the first Klingon main character to appear in Star Trek, and in 11 seasons as a regular character on TNG and then DS9, has appeared in more Star Trek franchise episodes than any other character.