Brendan Cowell (born 16 August 1976) is an Australian actor, screenwriter, comedian and director. Cowell was born in Sydney. He discovered acting by accident while waiting for his sister to come out of a rehearsal; he was then cast in a commercial at age 8. He attended Charles Sturt University in Bathurst to complete a Bachelor of Arts in Theatre/Media, originally considering journalism as a career option.

Cowell won the Patrick White Playwrights' Award for his third play Bed along with a collection of other awards. His play Ruben Guthrie showed at the Belvoir St Theatre in 2009 to sell-out houses. It has a new production at La Boite Theatre in 2011, starring Gyton Grantley and directed by David Berthold. His most famous acting role is playing the enigmatic Tom on Australian cable TV's Love My Way, for which he also wrote several episodes, and playing Todd for the first two seasons on Life Support on SBS TV, for which he also wrote sketches.

His most recent foray into film have included roles in the 2007 crime drama Noise, World War 1 war film Beneath Hill 60 and romantic comedy I Love You Too. He won some acclaim for his portrayal of the title role in Bell Shakespeare's 2008 Production of Hamlet and acted in Sydney Theatre Company's production of True West, directed by Philip Seymour Hoffman, in 2010. Brendan lives in Newtown, New South Wales Sydney and is a committed supporter of the Cronulla Sharks rugby league team.

In 2010 he published his first novel How it Feels.

In 2017 he starred as Galileo Galilei in the Young Vic's production of Bertholt Brecht's Life of Galileo.

Also in 2017, Cowell joined the cast of the HBO series Game of Thrones in Season 7 as Harrag, an Ironborn sea captain allied to Theon Greyjoy.