Worldwide, Sley (Sley 
) is a rare boy's given name. The forename Sley is habitual in the Democratic Republic of the Congo, where it is a rare boy's name, Tunisia, and Tanzania, where it is a very rare masculine name. Not in comparison with a country's population, it is commonest in the Democratic Republic of the Congo, Tanzania, and Brazil. Much less frequently, Sley is the last name as well as the forename.