Máel Dúin (died 1055) is the eighth alleged Bishop of St Andrews (or Cennrígmonaid). He is mentioned in the bishop-lists of the 15th-century historians Walter Bower and Andrew of Wyntoun as the successor of Bishop Ailín. Máel Dúin is known from other sources. A charter preserved in the Registrum of the Priory of St. Andrews, although probably translated into Latin from Gaelic at a later date, records a grant of the lands and church of Markinch by Bishop Máel Dúin (Maldunus) of St. Andrews to the Céli Dé of Loch Leven. Máel Dúin was succeeded in the bishopric by Túathal.