Anna Jagiellon  was queen of Poland from 1575 to 1586. She was the daughter of Poland's King Sigismund I the Old, and the wife of Stephen Báthory. She was elected, along with her then fiance, Báthory, as co-ruler in the second election of the Polish-Lithuanian Commonwealth. Anna was the last member of the Jagiellon dynasty.

• Royal titles, in Latin: Anna Dei Gratia Infans Regni Poloniae.

• English translation: Anna, by the Grace of God, Infanta of the Kingdom of Poland.

Anna was born in 1523 to the Jagiellon King, Sigismund I the Old and his wife Bona Sforza. Her early life was rather mundane. She embroidered church vestments, was involved in works of charity, and fulfilled her obligations as a princess. Anna gave up her suitor the King of Sweden in favour of her sister Katherine. Anna remained unmarried until the age of fifty-two. Thirty-three years at the side of her overbearing mother had taught her not only patience and calmness, but also the conviction that a woman could be as good a monarch as a man.

However, in 1572, her brother Sigismund II Augustus died, leaving the thrones to the Polish-Lithuanian Commonwealth vacant. In 1572 Jean Montluc, Bishop of Valence, offered the French prince Henry to the electors of the commonwealth as the next King. Montluc promised the electors that Henry would marry Anna, "to maintain the dynastic tradition". Unfortunately, for Anna, after Henry was elected as the first monarch in the Polish-Lithuanian Commonwealth, he withdrew his promise and they never wed. In June 1574 Henry left Poland to assume his new duties as King of France and by May 1575 the Parliament of the Commonwealth had removed him as their monarch.

By the autumn of 1575 a new candidate was offered to the electors of the commonwealth, Stephen Báthory, Prince of Transylvania. Stephen had to agree to the condition that he would marry Anna Jagiellon, which he did.On 15 December 1575, near Warsaw, Anna along with Stephen Báthory, her fiance, was elected as co-rulers, as the second monarch in the Polish-Lithuanian Commonwealth with the dual title of King of Poland and Grand Duke of Lithuania The coronation took place in Krakow 1 May 1576.

With the death of her husband in 1586, she had one final play to influence the thrones of the Commonwealth. She put forth, to the electors, Sigismund III Vasa, the only son of her youngest sister, Catherine Jagellon of Poland, Queen of Sweden. With Anna's help he gained the Polish-Lithuanian Commonwealth thrones as the third elected monarch.

Anna died, during her nephew Sigismund's reign, in her own country, where she had been born and had lived, on 9 September 1596. She was the last member of the Jagiellons.

Warsaw was Anna's main residence before it became the capital and she embellished the city by funding the construction of a variety of structures, many of which still exist today. She also funded several distinguished tomb monuments in the Wawel Cathedral, including the monument of her brother King Sigismund Augustus and her own monument in Sigismund's Chapel (both 1574–1575, Santi Gucci) and her husband Stephen Báthory in the Chapel of the Blessed Virgin Mary (1586, Santi Gucci) as well as the tomb of mother Bona Sforza in the Basilica di San Nicola in Bari (1593). In 1586 (ten years after it was painted) she ordered that a portrait of her in coronation robes be placed in the Sigismund's Chapel.