Matthew Paige Damon (; born October 8, 1970) is an American actor, film producer, and screenwriter. Ranked among Forbes' most bankable stars, the films in which he has appeared have collectively earned over $3.88 billion at the North American box office, making him one of the highest-grossing actors of all time. He has received various awards and nominations, including an Academy Award and two Golden Globe Awards, in addition to nominations for three British Academy Film Awards and seven Primetime Emmy Awards.

Damon began his acting career in the film Mystic Pizza (1988). He gained prominence in 1997 when he and Ben Affleck wrote and starred in Good Will Hunting, which won them the Academy Award and Golden Globe for Best Screenplay. He established himself as a leading man by starring as Tom Ripley in The Talented Mr. Ripley (1999), Jason Bourne in the Bourne franchise (2002–2007; 2016), and con man Linus Caldwell in the Ocean's trilogy (2001–2007). Damon's other notable performances were in Saving Private Ryan (1998), Syriana (2005), The Departed (2006), The Informant! (2009), Invictus (2009), True Grit (2010), Contagion (2011), Ford v Ferrari (2019), Stillwater (2021), The Last Duel (2021), and Air (2023). He won the Golden Globe Award for Best Actor for playing an astronaut stranded on Mars in The Martian (2015).

On television, Damon has portrayed Scott Thorson in the HBO biopic Behind the Candelabra (2013) for which he was nominated for a Primetime Emmy Award. He has guest-starred on 30 Rock in 2011 and Saturday Night Live in 2019. He also produced the reality series Project Greenlight (2001–2015) as well as the film Manchester by the Sea (2016). Damon has performed voice-over work in both animated and documentary films, and has established two production companies with Affleck. He has been involved in charitable work with organizations including the One Campaign, H2O Africa Foundation, Feeding America, and Water.org.