Infanta Maria of Portugal (Coimbra, 21 November 1264 – Coimbra, 6 June 1304; Portuguese pronunciation: [m?'?i?]) was a Portuguese infanta (princess) daughter of King Afonso III of Portugal and his second wife Beatrice of Castile.
Maria was born on 21 November 1264 in Coimbra and was for the majority of her life a nun in the Convent of the Lady Canons of Saint John (Convento das Donas Cónegas de São João), near the Monastery of Santa Cruz of Coimbra.