Graham John Yost (born September 5, 1959) is a Canadian film and television screenwriter. His most famous works are the hit 1994 film Speed, Broken Arrow, and Hard Rain.
He has also written for the television series Herman's Head, Band of Brothers, and Boomtown. More recently, he was the creator of the short-lived NBC drama Raines. He has also teamed up with Tom Hanks and Steven Spielberg, along with two of his fellow Boomtown writers Michelle Ashford and Larry Andries, to write and direct episodes of the HBO miniseries The Pacific. In 2010, Yost is the creator and executive producer on the series Justified, which premiered on FX in March 2010.