Brett Clifford Gelman is an American actor and comedian. He was born on October 6, 1976, in Highland Park, Illinois. He is best known for his roles as Murray Bauman in the Netflix series Stranger Things and Martin on the BBC series Fleabag.

Gelman began his career as a comedian in the early 2000s. He performed in numerous comedy clubs and improv theaters in New York City. In 2009, he was a writer and performer on the sketch comedy series Eagleheart. He also had a recurring role on the comedy series Another Period.

In 2016, Gelman was cast as Murray Bauman in the third season of Stranger Things. His character is a conspiracy theorist who helps the main characters investigate the supernatural events in Hawkins, Indiana. Gelman has since appeared in all four seasons of the show.

In 2016, Gelman also starred in the BBC series Fleabag. He played Martin, the boyfriend of the show's main character, Fleabag. Gelman's performance was critically acclaimed, and he was nominated for a Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series.

Gelman has also appeared in numerous films, including The Other Guys (2010), 30 Minutes or Less (2011), and A Very Harold & Kumar 3D Christmas (2011). He has also had recurring roles on the television shows Go On, Married, and Camping.