Elizabeth of Portugal (1271–1336) was queen consort of Portugal and a Saint of the Roman Catholic Church. She is also know as Queen Saint Elizabeth (in Portuguese: Rainha Santa Isabel).

She was named after her great-aunt Elizabeth of Hungary, but is known in Portuguese by "Isabel". The daughter of Peter III of Aragon, and Constantia, grandchild of Frederick II, Holy Roman Emperor, she showed an early enthusiasm for religion: she said the full Divine Office daily, fasted and did other penances, and gave up amusement.

Elizabeth was married very early to Denis of Portugal, a poet, and known as Rei Lavrador, or the farmer king, because he planted some pine forest, near Leiria, the wood from these trees would later be used to make the boats during the discoveries. Elizabeth quietly pursued the regular religious practices of her maidenhood, and was devoted to the poor and sick. Naturally, such a life was a reproach to many around her, and caused ill will in some quarters. A popular story is told of how her husband's jealousy was roused by an evil-speaking page; of how he condemned the queen's supposed guilty accomplice to a cruel death; and was finally convinced of her innocence by the strange accidental substitution of her accuser for the intended victim.

They had two children, a daughter Constance, who married Ferdinand IV of Castile, and a son Afonso (later Afonso IV of Portugal). The latter so greatly resented the favours shown to the king's illegitimate sons that he rebelled, and in 1323 war was declared between him and his father. Elizabeth, however, reconciled her husband and son, and is known in consequence as the "peacemaker".

Denis died in 1325, his son succeeding him. Elizabeth then retired to a convent of the Poor Clares which she had founded at Coimbra, where she took the habit of the Franciscan Order, wishing to devote the rest of her life to the poor and sick in obscurity. But she was called forth to act once more as peacemaker. In 1336 Afonso IV marched his troops against the Alfonso XI of Castile, to whom he had married his daughter Maria, and who had neglected and ill-treated her. In spite of age and weakness, the queen dowager insisted on hurrying to Estremoz, where the two king's armies were drawn up. She again stopped the fighting and caused terms of peace to be arranged. But the exertion brought on her final illness; and as soon as her mission was fulfilled she died of a fever.

Elizabeth was buried at Coimbra, and miracles were said to have followed her death. She was canonized by Pope Urban VIII in 1625, and her feast is kept on the 4th of July (formerly the 8th).