William Gaither Crudup (born July 8, 1968) is an American actor. He is a four-time Tony Award nominee, winning once for his performance in Tom Stoppard's play The Coast of Utopia in 2007. He has starred in numerous high-profile films, including Without Limits, Princess Mononoke, Almost Famous, Big Fish, Mission: Impossible III, Watchmen, Public Enemies, Spotlight, Jackie, The Stanford Prison Experiment, Justice League, and Alien: Covenant, in both lead and supporting roles. He has been nominated for an Independent Spirit Award for Best Male Lead for his performance in Jesus' Son, and received two Screen Actors Guild Award nominations as part of an ensemble cast for Almost Famous and Spotlight, winning for the latter.

Crudup starred in the streaming television series Gypsy (2017) and The Morning Show (2019), the latter of which earned him a Primetime Emmy Award and a Critics' Choice Television Award.