Ida of Austria (c. 1055 – September 1101) was a Margravine of Austria by marriage to Leopold II of Austria. She was a crusader, participating in the Crusade of 1101 with her own army.
In 1101, Ida, alongside Thiemo of Salzburg and the dukes Welf IV of Bavaria and William IX of Bavaria, joined the Crusade of 1101, and raised and led her own army toward Jerusalem.
In September of that year, Ida and her army were among those ambushed at Heraclea Cybistra by the sultan Kilij Arslan I. Ekkehard of Aura reports that Ida was killed in the fighting, but rumors persisted that she survived, and was carried off to a harem. Later legends claimed that she was the mother of the Muslim hero Zengi, but this is impossible on chronological grounds.
Ida's fate is depicted in Beloved Pilgrim by Christopher Hawthorne (2011).
- Leopold III (1073–1136), who succeeded his father as Austrian margrave,
- Adelaide (d. after 1120), married Count Theoderic II of Formbach
- Elizabeth (d. 1107), married Margrave Ottokar II of Styria
- Gerberga (d. 1142), married Duke Bořivoj II of Bohemia
- Ida, married the Přemyslid prince Luitpold of Znojmo
- Euphemia, married Count Conrad I of Peilstein
- Sophia (d. 1154), married Henry of Eppenstein, Duke of Carinthia from 1090 to 1122, and secondly Count Sieghard X of Burghausen.