Maria of Portugal, Marchioness of Tortosa

Maria of Portugal (Portuguese pronunciation: [mɐˈɾiɐ]; 6 April 1342, in Évora, Kingdom of Portugal – 1377, in Genoa, Republic of Genoa, Italy) was a Portuguese infanta (princess) member of the House of Burgundy and by marriage marchioness of Tortosa and lady of Albarracín.

She was the eldest child and daughter of King Peter I of Portugal and his wife Constance Manuel. Her parents' marriage produced four children, but only infanta Maria and her younger brother, the future King Ferdinand I of Portugal, survived adulthood; from her father's relationship (or second marriage) with Inês de Castro and later affair with Teresa Lourenço, she had several half-siblings, including Beatrice, countess of Alburquerque, and John of Aviz, who became king of Portugal in 1385 and founder of the House of Aviz, who ruled the Kingdom of Portugal until 1580.