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

His film roles include 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 done voice acting for The SpongeBob SquarePants Movie (2004), Monsters vs. Aliens (2009), Tangled (2010), and Trolls (2016). For his voice role in The Lionhearts (1998), he was nominated for a Daytime Emmy Award. From 2002 to 2003, he was an announcer for Hollywood Squares.