Castleboy may refer to:
Castleboy Tower, a folly in County Galway, Ireland Castleboy Preceptory, of the Knights Hospitaller, in County Down, Northern Ireland; see List of monastic houses in County Down Castleboy (civil parish), parish and townland in County Down, Northern Ireland A townland in County Galway, Ireland; List of townlands of County Galway Two townlands in County Meath, Ireland; see List of townlands of County Meath