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 a Screen Actors Guild Award as well as nominations for eight Golden Globe Awards and two Tony Awards. Martin received the Mark Twain Prize for American Humor in 2005, the Kennedy Center Honors in 2007, the Honorary Academy Award in 2013 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.

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 American stand-up comedians during the 1970s, performing his brand of offbeat, absurdist comedy routines before sold-out theaters on national tours. He then starred in films such 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), Bringing Down the House (2003), 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. Martin 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. He has won three Grammy Awards for his music and two for his comedy albums Let's Get Small (1977) and A Wild and Crazy Guy (1978).

Stephen Glenn Martin was born on August 14, 1945, in Waco, Texas, the son of Mary Lee (née Stewart; 1911–2002) and Glenn Vernon Martin (1914–1997), a real estate salesman and aspiring actor. He has an older sister, Melinda.

Martin is of English, Scottish, Welsh, Scots-Irish, German, and French descent. He and his sister grew up in a Baptist family in Inglewood, California, and later in Garden Grove in Orange County; he was a cheerleader at Garden Grove High School. One of Martin's earliest memories is seeing his father as an extra serving drinks onstage at the Callboard Theater on Melrose Place in West Hollywood. During World War II in Britain, his father appeared in a production of Our Town with Raymond Massey. Expressing his affection through gifts like cars and bikes, Steve's father was stern and not emotionally open to his son. He was proud but critical, with Steve later recalling that in his teens his feelings for his father were mostly of hatred.

Steve Martin's first job was at newly opened Disneyland, selling guidebooks on weekends and full-time during summer break. The work lasted for three years (1955–1958). During his free time, he frequented the Main Street Magic shop, where tricks were demonstrated to patrons. While working at Disneyland, he was captured in the background of the home movie that was made into the short-subject film Disneyland Dream, incidentally becoming his first film appearance. By 1960, he had mastered several magic tricks and illusions and took a paying job at the Magic shop in Fantasyland in August. There he perfected his talents for magic, juggling, and creating balloon animals in the manner of mentor Wally Boag, frequently performing for tips.

In his authorized biography, close friend Morris Walker suggests that Martin could "be described most accurately as an agnostic ... he rarely went to church and was never involved in organized religion of his own volition". In his early 20s, Martin dated Melissa Trumbo, daughter of novelist and screenwriter Dalton Trumbo.