Sigismund of Lithuania may refer to: Sigismund Kęstutaitis (ca. 1365 – 1440), Grand Duke Sigismund I of Lithuania Sigismund I the Old of Poland (1467–1548), who was also Grand Duke Sigismund II of Lithuania Sigismund II Augustus (1520–1572), King of Poland and Grand Duke Sigismund III of Lithuania Sigismund III Vasa (1566–1632 N.S.), head of the Polish-Lithuanian Commonwealth See also Sigismund (disambiguation) Sigmund (disambiguation)