Ryan Daniel Montgomery (born July 5, 1977), better known by his stage name Royce da 5'9", is an American rapper. He is known for his longtime association with Eminem and for his solo career, recording primarily with Carlos "6 July" Broady and DJ Premier, as well as ghostwriting for the likes of Diddy and Dr. Dre. Royce is one half of the rap duo Bad Meets Evil with Eminem and also a member of hip hop group Slaughterhouse. The editors of About.com ranked him #33 on their list of the Top 50 MCs of Our Time (1987–2007).

Ryan Montgomery was born and raised on the West side of Detroit, Michigan on W. McNichols & Wyoming Ave. He moved to Oak Park, Michigan when he was 10 years old, later acquiring the nickname "Royce" during high school after wearing a Turkish link chain with an R pendant resembling the Rolls Royce symbol. He started rapping at age 18, influenced mainly by Ras Kass and Redman. He signed his first deal in 1998 with Tommy Boy Records, after the label shut down, he signed a deal with Columbia where he started recording an album called Rock City, referring to Detroit's former status as home to Motown Records. When the project was heavily bootlegged, Royce left the label for Koch to re-record some of the album, eventually releasing it in 2002 as Rock City (Version 2.0). While the album did not sell very well, the DJ Premier-produced single "Boom" gained Royce some underground recognition and eventually resulted in the two working together more closely.