Zachary Knight Galifianakis (/ˌɡælɪfəˈnækɪs/; born October 1, 1969) is an American comedian and actor. He is known for his role as Alan in The Hangover trilogy (2009–2013). On television, he starred in the FX series Baskets (2016–2019), which he was nominated for the Primetime Emmy Award for Outstanding Lead Actor in a Comedy Series in 2017. He also hosted the Funny or Die talk show Between Two Ferns with Zach Galifianakis (2008–2018).

Galifianakis's other films include Due Date (2010), It's Kind of a Funny Story (2010), The Campaign (2012) and Birdman or (The Unexpected Virtue of Ignorance) (2014). He has also voiced characters in animated films such as Puss in Boots (2011), The Lego Batman Movie (2017), Missing Link (2019), Ron's Gone Wrong (2021) and The Bob's Burgers Movie (2022).