Stephen Glenn Martin (born August 14, 1945) is an American comedian, actor, writer, producer, and musician. Known for his work in comedy films, television, and recording, he has received many accolades, including five Grammy Awards, a Primetime Emmy Award and an Honorary Academy Award, in addition to nominations for two Tony Awards. He also received the Mark Twain Prize for American Humor in 2005, the Kennedy Center Honors in 2007, and an AFI Life Achievement Award in 2015. In 2004, Comedy Central ranked Martin at sixth place in a list of the 100 greatest stand-up comics. The Guardian named him one of the best actors never to have received an Academy Award nomination.

Martin first came to public notice as a writer for The Smothers Brothers Comedy Hour, for which he won a Primetime Emmy Award in 1969, and later as a frequent host on Saturday Night Live. He became one of the most popular U.S. stand-up comedians during the 1970s, performing his brand of offbeat, absurdist comedy routines before sold-out theaters on national tours. Martin went on to star in film roles, including such films as The Jerk (1979), Dead Men Don't Wear Plaid (1982), The Man with Two Brains (1983), All of Me (1984), ¡Three Amigos! (1986), Planes, Trains and Automobiles (1987), Dirty Rotten Scoundrels (1988), L.A. Story (1991), Bowfinger (1999) and Looney Tunes: Back in Action (2003). He played family patriarchs in Parenthood (1989), the Father of the Bride films (1991–1995), and the Cheaper by the Dozen films (2003–2005).

Since 2015, Martin has embarked on several national comedy tours with fellow comedian Martin Short. In 2018, they released their Netflix special An Evening You Will Forget for the Rest of Your Life which received four Primetime Emmy Award nominations. In 2021, he co-created and starred in his first television show, the Hulu comedy series Only Murders in the Building, alongside Short and Selena Gomez, for which he earned three Primetime Emmy Award nominations, two Screen Actors Guild Award nominations, a Golden Globe Award nomination, and a 2021 Peabody Award nomination. In 2022, Martin and Short co-hosted Saturday Night Live together with Gomez making an appearance.

Martin is also known for writing the books to the musical Bright Star (2016) and to the comedy Meteor Shower (2017), both of which premiered on Broadway; he co-wrote the music to the former. He has played banjo since an early age and has included music in his comedy routines from the beginning of his professional career. He has released several music albums and has performed with various bluegrass acts, including Earl Scruggs, with whom he won a Grammy for Best Country Instrumental Performance in 2002. His first solo music album, The Crow: New Songs for the 5-String Banjo (2009) received the Grammy Award for Best Bluegrass Album.