Richard Allen Garriott de Cayeux (né Garriott) is a British-born American video game developer, entrepreneur and private astronaut.

Garriott, who is the son of NASA astronaut Owen Garriott, was originally a game designer and programmer, and is now involved in a number of aspects of computer-game development. On October 12, 2008, Garriott flew aboard the Soyuz TMA-13 mission to the International Space Station as a private astronaut, returning 12 days later aboard Soyuz TMA-12. He became the second space traveler, and first from the United States, to have a parent who was also a space traveler. During his ISS flight, he filmed a science fiction movie Apogee of Fear.

The creator of the Ultima game series, Garriott was involved in all games in the series, and directly supervised all eleven main installments, starting with 1979's Akalabeth: World of Doom and concluding with 1999's Ultima IX: Ascension. Within the context of Ultima, Garriott presented himself as the fictional persona of Lord British. The series is considered influential, notably helping with establishing the computer role-playing game genre. He founded the video game development company Portalarium in 2009. He was CEO of Portalarium and creative director of Shroud of the Avatar: Forsaken Virtues until 2018 when he shed the title, later relinquishing all Shroud of the Avatar assets to Catnip Games in 2019.