McCauley is derived from the patronymic form of two different Gaelic names.
[1] According to Edward MacLysaght, Gawley is derived from the Irish Mag Amhlaoibh.
MacLysaght stated that, in Ireland, the surname is borne by members of a sept of the Maguires in Fermanagh, and also by descendants of the Scottish Clan MacAulay who settled in Ulster.
[2] In some cases, the surname Gawley is an Americanization of the German Colle.
It may be derived from a nickname meaning "bald" or "naked"; or it can be derived from a topographic name, or a habitational name, meaning "bare heathland" or "place without trees".