Hedwig Jagiellon (Lithuanian: Jadvyga Jogailaitė, Polish: Jadwiga Jagiellonka) (8 April 1408 – 8 December 1431) was a Polish and Lithuanian princess, member of the Jagiellon dynasty.
She was the only daughter of Wladyslaw Jagiello, King of Poland and Grand Duke of Lithuania by his second wife Anna, daughter of William, Count of Celje and Anna, in turn daughter of King Casimir III of Poland. In consequence, Anna of Celje was a Piast heiress and thanks to his marriage with her in 1402, Jagiello re-legitimized his rule as King of Poland after the death of his first wife Hedwig (Jadwiga), who reigned as King (not Queen consort) of Poland. Their only daughter, born in 1408, received her name after Queen Hedwig.
After it became apparent that Anna of Celje would not be able to bear any further children, Hedwig was officially proclaimed heiress to the throne during a congress in Jedlnia, in 1413.
Queen Anna died in 1416, leaving Hedwig as her sole surviving child. In 1417 Jogaila married Elisabeth of Pilica, and in 1422, Sophia of Halshany, who gave birth to two sons. Hedwig was raised by both stepmothers.
In 1419, a marriage to Bogislaw IX, Duke of Pomerania was proposed, but his indecisiveness ended the negotiations. On 12 April 1421, Hedwig was betrothed to Frederick, second son of Frederick I, Elector of Brandenburg. According to the terms of the agreement, the marriage could took place when Frederick reached a proper age, by 1427, and also the young Brandenburg prince had to live in Poland as soon as was possible, in order to get acquainted with the language and customs of his future country.
A party of Polish nobles wanted Hedwig and her future husband to succeed her father, instead of her father's sons by Sophia of Halshany, who were not descended from the Piast dynasty of Poland. The death of her maternal grandmother in 1425 left Hedwig without any close relatives.
In early 1430 King Janus of Cyprus asked for her hand in marriage but Hedwig suddenly died.