O'Flaherty is an Irish Gaelic clan based most prominently in what is today County Galway. The clan name originated in the 10th century as a derivative of its founder Flaithbheartach mac Eimhin. They descend in the paternal line from the Connachta's Uí Briúin Seóla. They were originally kings of Maigh Seóla and Muintir Murchada and as members of the Uí Briúin were kinsmen of the Ó Conchubhair and Mac Diarmada amongst others. After their king Cathal mac Tigernán lost out to Áed in Gai Bernaig in the 11th century, the family were pushed further west to Iar Connacht, a territory associated with Connemara today. They continued to rule this land until the 16th century. The name has been alternatively rendered into English in various forms, such as Flaherty, Fluharty, Faherty, Laverty, Flaverty, Lahiff, and Flahive.

West Connacht was a kingdom of Gaelic Ireland, associated geographically with present-day County Galway, particularly the area known more commonly today as Connemara. The kingdom represented the core homeland of the Connachta's Uí Briúin Seóla kindred and although they ruled, there were smaller groups of other Gaels in the area, such as the Delbhna Tir Dha Locha and the Conmhaícne Mara. It existed from 1051 onwards, after the Ó Conchobhair, Kings of Connacht, pushed the Ó Flaithbheartaigh to the West of Lough Corrib, from their original territory of Maigh Seóla. Iar Connacht remained a subordinate túath of Connacht, until the 13th century, after which it was more independent.