Zachary Knight Galifianakis (; born October 1, 1969) is an American actor, writer and comedian. He came to prominence with his Comedy Central Presents special in 2001 and presented his own show called Late World with Zach on VH1 the following year. He has also starred in films, such as The Hangover trilogy (2009–2013), Due Date (2010), The Campaign (2012), Birdman or (The Unexpected Virtue of Ignorance) (2014), Masterminds (2016) and The Lego Batman Movie (2017).

He currently hosts the Emmy Award-winning talk show Between Two Ferns with Zach Galifianakis on the Funny or Die website, and executive produces, writes and stars in the dark comedy series Baskets on FX.