Esterka Małach

Esterka Małach, traditionally called Esterka, was a fourteenth-century Jewish woman whom the chronicler Jan Długosz, writing under the year 1356, named as the beloved mistress of King Casimir III the Great. Said to be the granddaughter of a merchant and physician of Opoczno, she was credited with prompting the king's favourable privileges for the Jews of Poland.

Długosz wrote that she bore the king two sons, Niemira and Pełka. In his chronicle Marcin Bielski wrote that Casimir set aside a Bohemian mistress and took Esterka in her place.