Jeffrey Michael Tambor (born July 8, 1944) is an American actor and comedian. He is known for his television roles, such as Jeffrey Brookes, the uptight neighbor Stanley and Helen Roper in the sitcom The Ropers (1979–1980), Hank Kingsley in The Larry Sanders Show (1992–1998), George Bluth Sr. and Oscar Bluth in Arrested Development (2003–2006, 2013, 2018–2019), and Maura Pfefferman in Transparent (2014–2017). For his role in the latter, Tambor received two Primetime Emmy Awards for Outstanding Lead Actor in a Comedy Series out of three nominations. In 2015, he also received a Golden Globe Award for his portrayal of Pfefferman.

Among his film roles are Jay Porter in ...And Justice for All (1979), Jinx Latham in Mr. Mom (1983), Sully in There's Something About Mary (1998), Mayor Augustus Maywho in How the Grinch Stole Christmas (2000), Tom Manning in Hellboy (2004) and its sequel Hellboy II: The Golden Army (2008), Sid Garner in The Hangover trilogy (2009–2013), Francis Silverberg in The Accountant (2016), and Georgy Malenkov in The Death of Stalin (2017).

Tambor has voiced roles in The SpongeBob SquarePants Movie (2004), Monsters vs. Aliens (2009), Tangled (2010), and Trolls (2016). For his voice work in The Lionhearts (1998), he was nominated for a Daytime Emmy Award. From 2002 to 2003, he was an announcer on Hollywood Squares.