Madadhan is a surname. Notable people with the surname include:
Ambrose Ó Madadhan, first Prior of Portumna Priory
Anmchadh Ó Madadhan, Chief of the Name, died 1636
Breasal Ó Madadhan, Lord of Síol Anmchadha and Chief of the Name, died 1526
Cathal Ó Madadhan (died 1286), King of Síol Anmchadha
Diarmaid Cleirech Ua Madadhan (died 1207), King of Síol Anmchadha
Diarmaid Ua Madadhan (died 1135), King of Síol Anmchadha and Uí Maine
Domhnall Ó Madadhan, chief of Síol Anmchadha, fl. 1567 - after 8 March 1611
Eoghan Carrach Ó Madadhan, Chief of Síol Anmchadha, fl. 1451
Eoghan Mór Ó Madadhan, Chief of Síol Anmchadha, fl. 1371–1410
Eoghan Ó Madadhan, Chief of Síol Anmchadha, fl. 1314–1347
John Ó Madadhan, Lord of Síol Anmchadha and Chief of the Name, died 1556
Madudan Mór Ua Madadhan, King of Síol Anmchadha, died after 1158
Madudan Óg Ó Madadhan (died 1235), King of Síol Anmchadha
Madudan Reamhar Ua Madadhan, Chief of Síol Anmchadha, 1069–1095
Melaghlin Ua Madadhan (died 1188), King of Síol Anmchadha
Murcadh Ó Madadhan, Chief of Síol Anmchadha, died 1451
Murchadh Ó Madadhan, King of Síol Anmchadha, died 1327
Murchadh Reagh Ó Madadhan, Chief of Síol Anmchadha, died 1475
Owen Ó Madadhan, Lord of Síol Anmchadha and Chief of the Name, fl. 1475
Richard Ó Madadhan, Prior of Portumna Priory in 1691
