Guaglione is a Neapolitan song with music by Giuseppe Fanciulli and words by Nicola "Nisa" Salerno. It was the winning song at the IV Napoli Song Festival broadcast by radio in 1956. The song's title is Neapolitan language slang which translates to "street bum", "urchin", "back street boy", "corner boy" or "street tough". The word guaglione has appeared as "wallyo" in New York immigrant slang.

The song has been covered by various artists, including Italian bandleader Renzo Arbore, and Italian singers Claudio Villa, Aurelio Fierro and Renato Carosone. Under the title "The Man Who Plays the Mandolino", with a lyric in English, Dean Martin sang it in 1956 after Fred Raphael of Walt Disney Music Company obtained for Disney the U.S. publishing rights.

The best known version of "Guaglione" was recorded by the Cuban bandleader Perez Prado in 1958 as an uptempo mambo tune. As a mambo, the track rose to fame in 1995 after it was used for the Guinness advert "Anticipation". It has since been featured as the intro music for the 1996 video game Kingdom O' Magic, and more recently as the opening music for the television show Jimmy's Farm. The song is one of Disney's biggest profit makers.