The name Darcy is given to both a native Irish name, a corruption of O Dorchaidhe, and a Norman name, often spelt D'Arcy from Arci, a place in Normandy. The Norman name is most common in the east midlands of Ireland.

The Irish name which should never be spelt D'Arcy originated in County Mayo around Partry near Lough Mask. There were also septs in County Leitrim and east Galway. The family became one of the Tribes of Galway.