O'Cathal is a surname of Irish origin, derived from the Gaelic name Ó Cathail, which means "descendant of Cathal." The name Cathal itself translates to "battle ruler" or "mighty warrior." It is associated with various historical figures in Ireland, particularly in the province of Connacht. The O'Cathal family has roots in the Kingdom of Connacht, where they were known as a prominent clan. Over the centuries, members of the O'Cathal lineage have contributed to Irish history and culture, often linked to local leadership and land ownership. Today, the name can still be found among descendants in Ireland and the Irish diaspora.