Demetri Martin (born May 25, 1973) is an American comedian. He graduated from Yale before attending law school at New York University. He later dropped out to pursue a career in comedy.

The son of a Greek Orthodox priest and a nutritionist, Martin grew up with his brother and sister in Toms River, New Jersey. His parents co-owned a Greek diner with his grandparents and uncle. Martin, the prototypical good Greek boy, served as an altar boy at church and bused tables at the restaurant. He studied maniacally and, to his family’s delight, received a full scholarship to the New York University School of Law. After completing his second year, however, he said, "Fuck it. I’m going to be a stand-up comedian."

In 2003 he won the Perrier Comedy Award at the Edinburgh Fringe Festival with If I.... From 2003 to 2004 he was a writer for Late Night with Conan O'Brien.

Martin has had two specials on Comedy Central. One of his specials was divided into three parts, as follows: In the first segment of it he told regular jokes such as: "I wrapped my Christmas presents early this year, but I used the wrong paper. See, the paper I used said "Happy Birthday" on it. I didn't want to waste it so I just wrote "Jesus" on it." For the second segment he used humorous drawings to aid his jokes. He would use the images either as the punchline or just as a background. For the third segment Martin got a guitar and strummed it around the punchline. He then put on a pseudo-play where he would strum his guitar while talking; some of his comedian friends dressed as fairies and dragons and such would act according to the story he was telling ("where my jokes come from"). Martin's mother and grandmother also appeared.

Martin was the first person on a Comedy Central special to do the three major forms of stand-up comedy, appearing as a standup comic, a prop comic (such as The Amazing Jonathan), and as a musical comic (such as Stephen Lynch).

Recently, Martin appeared at the 2005 Edinburgh Fringe in a show called These Are Jokes. Since late 2005, he has been credited as a Correspondent on The Daily Show, for a segment called "Trend Spotting." He has used this segment to talk about so-called hip trends among youth such as wine and the Xbox 360. A piece about social networking featured his profile on MySpace.

According to his website, Martin is in the process of publishing a book of drawings. He also plans on rerecording a comedy album in Chicago within the coming months.