Sir Gareth was a Knight of the Round Table in Arthurian Legend. He was the son of Lot and Morgause, King Arthur's sister thus making him Arthur's nephew and brothers to Gawain, Gaheris, Agravaine, and Mordred. He came to Camelot in disguise as a kitchen boy and was set to work by Kay, who always gave him difficult work or teased him as being a lowly kitchen boy, nicknamed him "Beaumains" or "Goodhands" (alternatively "White Hands", or "Beautiful hands"), since he would not give his name.

Gareth is a character in Konami's role playing game Suikoden IV. He is an engraver who engraved the Rose Crest for Schtolteheim Reinbach III.

Gareth is a fictional character, one of the two heroes in Cross Gen Comics' now defunct comic book series Sojourn. Like his companion Arwyn, Gareth is not a superhero with superhuman powers, but he is a remarkably talented warrior with a magic sword (Serpent's Bane). The Sojourn series lasted for thirty-five issues, including a prequel.