Mario Dewar Barrett(born August 27, 1986) is an American R&B and pop singer. He is best known for his singles "Just a Friend 2002" (2002) and "Let Me Love You" (2004), which won him two Billboard awards, as well as for appearing in the films Step Up and Freedom Writers. In 2008 he has appeared on Season 6 of Dancing with the Stars.

Mario, who is African American, was born in Baltimore, Maryland where he grew up with his grandmother.

Mario said at the age of four that he wanted to become a singer and since then he was always dedicated to having a musical career. He was offered a record deal at the age of fourteen, signing with Clive Davis' J Records. His musical influences include Stevie Wonder, Fernando & Q-Bah, Shay and Claire from Fun X Marvin Gaye, Sam Cooke, Nat King Cole, Brian McKnight, Boyz II Men, Usher, and Joe. His first introduction to the music industry was the Dr. Dolittle 2 movie soundtrack in 2001.

Mario began recording his debut album Mario at age fifteen, a year before releasing it in July 2002. The lead single "Just a Friend 2002", was an instant success. As of 2006, his first album has sold over 700,000 copies.

After his debut album was released, Mario wanted to record an album that was more mature. He released his second album, Turning Point, in December 7, 2004. The album was more successful than his first, mainly because of the hit single "Let Me Love You". The single peaked at the number one on the Billboard Hot 100 for nine consecutive weeks.

Mario's third album Go is dedicated to his mom Shawntia Hardaway and was released in the U.S. on December 11, 2007.

His fourth album should be released in late 2008. The singer has explained that he had about 70 songs concepts on his mind before doing "Go", and he only used few of them, so he’s planning on putting the rest on this following album.