Ratso may refer to:
People nickname of John Hiller (born 1943), Canadian former Major League Baseball relief pitcher nickname of Larry Sloman, American author best known for his collaboration with Howard Stern
Fictional characters "Ratso" Rizzo, a main character in the film Midnight Cowboy and the novel on which it is based Ratso the Rat, on the 1981 Saturday morning cartoon The Kwicky Koala Show Ratso, on the 2000–2005 American animated TV show Jackie Chan Adventures Ratso, on the 1988–1989 anime Wowser Ratso, on the 1970–1971 American animated TV show Groovie Goolies Ratso, in the films The Brave Little Toaster to the Rescue and The Brave Little Toaster Goes to Mars