Rhyming slang is a form of slang word construction in the English language. It is especially prevalent among Cockneys in England, and was first used in the early 19th century in the East End of London; hence its alternative name, Cockney rhyming slang. In the US, especially the criminal underworld of the West Coast between 1880 and 1920, rhyming slang has sometimes been known as Australian slang.

Cockney is a dialect of the English language, mainly spoken in London and its environs, particularly by Londoners with working-class and lower middle-class roots. The term Cockney is also used as a demonym for a person from the East End, or, traditionally, born within earshot of Bow Bells.