Muiredach (Old Irish), Muireadhach or Muireach, anglicized variously to Murdoch, Murtagh, Murdac, Mordacq and other forms, is a Goidelic name (meaning "chieftain") popular in Scotland and Ireland in the Middle Ages:
Muiredach Bolgrach, mythological Irish kingMuiredach Tirech, legendary high-king of IrelandMuiredach mac Eógain (died 489), legendary early king of AilechMuiredach Muinderg (died 489), legendary king of the UlaidMuiredach of Killala, reputed early Irish saintMuiredach Muillethan (died 702), king of ConnaughtMuiredach mac Ainbcellaig (died c. 770), king of Dál RiataMuiredach mac Murchado (died 760), king of LeinsterMuiredach mac Brain (died 818) (8th-century–818), king of LeinsterMuiredach mac Ruadrach (8th-century–829), king of LeinsterMuiredach mac Eochada (died 839), king of the UlaidMuiredach mac Brain (died 885), king of MunsterMuiredach mac Eochocáin (died 895), king of the UlaidMuireadhach Ua Carthaigh (died 1067), Chief Poet of ConnachtMuireadhach Ua Dubhthaigh, Archbishop of ConnachtMuireadhach Ua Flaithbheartaigh (died 1121), King of Iar ConnachtMuiredach (ealdorman) (fl. 958–963), ealdormanMuireadhach I, Earl of Menteith (fl. 12th-century–13th-century), Scottish mormaerMuireadhach Albanach (fl. early 12th-century–13th-centuryth century), Gaelic poet and crusaderMuireadhach II, Earl of Menteith (died c. 1230), Scottish mormaerMuireadhach III, Earl of Menteith (died 1332), Scottish mormaerMuireadhach of Inchaffray (died 1340s), Scottish abbotMuireadhach Sdíbhard or Muireadhach IV, Earl of Menteith (died 1425), Scottish prince