Louis Sebastian Theroux (/ˈluːi θəˈruː/; born 20 May 1970) is a British-American documentary filmmaker, journalist, broadcaster, and author. He has received two British Academy Television Awards and a Royal Television Society Television Award.

After graduating from Oxford University, Theroux moved to the US and worked as a journalist for Metro Silicon Valley and Spy. He moved into television as the presenter of offbeat segments on Michael Moore's TV Nation series and later began to host his own documentaries, including Louis Theroux's Weird Weekends, When Louis Met..., and several BBC Two specials.