Riley can be derived from two different sources. As an Irish name, it is a variant of Reilly and an anglicised form of the name Raghailleach, the meaning of which is unknown. It can also be derived from a place name meaning "rye clearing" in Old English. It is used as both a given name and surname. While traditionally a boys name, over time it has become more unisex. It began gaining significant popularity in the late 1990s and early 2000s.