Mary of Hungary (in Hungarian and Slovakian: Mária) was the second of three daughters of Louis I the Great of Hungary from the House of Angevin (Anjou). She was born around 1372. Her father had arranged that Sigismund of Luxembourg would marry one of his daughters (either Mary or Hedwig, who became Queen Jadwiga of Poland.)

Mary became Queen of Hungary after her father's death in 1382 (her elder sister Catherine died four years earlier). The country was ruled by her mother the Dowager Queen Elizabeth and by Palatine Miklós Garai. Many noblemen of Hungary were opposed to them and they helped Charles of Durazzo (Charles III of Naples, Charles II of Hungary) to become King of Hungary in 1385. Queen Elizabeth and Garai had Charles II assassinated in 1386. The supporters of Charles II captured Elizabeth and Mary. On the anniversary of the death of Charles II, Elizabeth was strangled before Mary's eyes.

Mary was rescued from captivity by Sigismund to whom she was betrothed. Sigismund took revenge on the murderers of Elizabeth. From 1387 officially Mary and Sigismund were joint rulers of Hungary but in fact Sigismund ruled alone. Mary died in 1395. In 1410 (after her death) Sigismund was elected Holy Roman Emperor.