Reginald Endicott Barclay III is a fictional engineer from the Star Trek media franchise. On television and in film, he has been portrayed by Dwight Schultz since the character's introduction in the Star Trek: The Next Generation third season episode "Hollow Pursuits." Schultz played the character for five episodes and one feature film of The Next Generation, as well as six episodes of the series Star Trek: Voyager. Barclay also appears in non-canon Star Trek novels and video games.

William Dwight Schultz is an American television, film and voice actor.