The Best Documentary Screenplay honor went to "Searching for Sugar Man."
The WGA also presented TV's "Breaking Bad" with its Best Drama Writing trophy, while "Louie" won the award for Best Comedy Writing.
"Girls" earned the accolade for Best Writing in a New Series and "The Young and the Restless" garnered the gong for Best Writing in a Daytime Drama.
Notable deaths of 2014 [PHOTOS]
'True Detective' adds Kelly Reilly