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 in 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. 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 supernatural events in Hawkins, Indiana. Since then, Gelman has appeared in all four seasons of the show.

In 2016, Gelman also appeared in the BBC series Fleabag. He played Martin, the boyfriend of the series' main character, Fleabag. Gelman's performance was highly praised by critics, and he was nominated for a Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series.