Bradford Claude "Brad" Dourif is an American film and television actor who gained early fame for his portrayal of Billy Bibbit in One Flew Over the Cuckoo's Nest.

He has since appeared in a number of memorable roles, including the voice of Chucky in the Child's Play franchise, Younger Brother in Ragtime, the mentat Piter De Vries in David Lynch's Dune, Gríma Wormtongue in The Lord of the Rings, the homicidal Betazoid Lon Suder in the TV series Star Trek: Voyager, serial killer Charles Dexter/Brother Edward in the acclaimed science fiction television series Babylon 5, and Doc Cochran in the HBO television series Deadwood.

Dourif has also worked with renowned film director Werner Herzog at many occasions, appearing in Scream of Stone, The Wild Blue Yonder, Bad Lieutenant: Port of Call New Orleans and My Son, My Son, What Have Ye Done?