Justin Paul Theroux (; born August 10, 1971) is an American actor and filmmaker. He gained recognition for his work with director David Lynch in the mystery film Mulholland Drive (2001) and the thriller film Inland Empire (2006). He also appeared in films such as Romy and Michele’s High School Reunion (1997), American Psycho (2000), Charlie’s Angels: Full Throttle (2003), Strangers with Candy (2005), Wanderlust (2012), The Girl on the Train (2016), The Spy Who Dumped Me (2018), On the Basis of Sex (2018), and Lady and the Tramp (2019).
Theroux is further known as a screenwriter for films such as the action comedy Tropic Thunder (2008), the superhero film Iron Man 2 (2010), and the musical comedy drama Rock of Ages (2012). He made his directorial debut with the romantic comedy film Dedication (2007).
Theroux starred as Kevin Garvey in the HBO mystery drama series The Leftovers (2014–2017), for which he was nominated for the Critics’ Choice Television Award for Best Actor in a Drama Series. He also starred as Dr. James Mantleray in the Netflix comedy drama miniseries Maniac (2018). In 2021, he portrayed Allie Fox in the Apple TV+ adaptation of The Mosquito Coast, based on the novel by his uncle Paul Theroux.