McNally is an Irish surname with two distinct and unrelated origins. In Ulster, particularly in County Tyrone, it comes from the Gaelic Mac Conallaidh, meaning "son of the wild hound" (i.e., wolf), and is associated with the Cenél nEógain branch of the Northern Ó Néill clans, prevalent in counties Antrim, Armagh, and Monaghan. In Connacht, especially in County Mayo, the surname—often spelled Nally—derives from Mac an Fhailghigh, meaning "son of the poor man," which has Norman roots as a Gaelicized form of Le Poer, referring to a religious vow of poverty rather than ordinary impoverishment. The name has been borne by many notable figures across diverse fields, including baseball pitcher Dave McNally, tennis player Caty McNally, and publisher Andrew McNally (1836–1904). This dual heritage highlights a striking contrast between a fierce "wolf" lineage in the north and a humble "poor man" lineage in the west.