Wulfhilde Billung of Saxony (1072 – 29 December 1126) was the eldest daughter of Magnus, Duke of Saxony and his wife, Sophia of Hungary.

In about 1095 she married Duke Henry IX of Bavaria.^[1] As a result of this marriage, part of the Billung possessions came into the hands of the House of Guelph. They had the following children:

• Henry X^[1]
• Conrad (died: 17 March 1126 in Bari, buried in Molfetta), a Cistercian monk and saint
• Sophia

• Judith^[1]
• Matilda (d. 1138), married Margrave Diephold IV of Vohburg (d. 1130) and Count Gebhard III of Sulzbach (d. 1188)
• Welf VI
• Wulfhilde, married Rudolf I, Count of Bregenz (d. 1160)

Wulfhilde died in 1126 and was buried at Weingarten Abbey.