Ó Cuinleáin is a surname of Irish origin, commonly associated with the Gaelic language. It is derived from the personal name Cuinleáin, which means "descendant of Cuinleán." The name is primarily found in the province of Connacht, particularly in counties like Galway and Roscommon. The Ó Cuinleáin family has historical ties to the region, often linked to the ancient Gaelic nobility. Like many Irish surnames, it reflects the rich cultural heritage of Ireland and the significance of lineage in Irish society. The name is part of the broader tradition of Irish surnames that often denote ancestry and clan affiliation.