Adalbert II, Count of Ballenstedt (about 1030 – 1076/83) from the House of Ascania, the 23rd Great-Grandfather of Elizabeth II, was Graf in Saxony and Vogt of Nienburg Abbey.
Adelbert was born at Ballenstedt in Eastphalia, the son of Esiko, Count of Ballenstedt and his wife Mathilde, probably a daughter of Duke Herman II of Swabia. About 1068 he married Adelheid, daughter of Margrave Otto I of Meissen and his wife Adele. Their two sons were Otto the Rich and Siegfried of Ballenstedt, later Count Palatine of the Rhine.
According to chronicler Lambert of Hersfeld, Adalbert supported Margrave Dedi I of the Saxon Eastern March in his 1069 conflict with King Henry IV. Dedi from the House of Wettin had married Adalbert's mother-in-law Adele, widow since 1067, and claimed the possessions of her deceased husband Otto of Meissen. Both had to surrender in short order, Adalbert however remained a fierce opponent of the king. From 1073 on he participated in the Great Saxon Revolt under Otto of Nordheim for which he was arrested in 1075. Even after his release he backed antiking Rudolf of Rheinfelden until he was finally killed in a feud at Westdorf near Aschersleben by one of Henry's liegemen.
Adalbert's widow married Count Palatine Hermann II of Lotharingia from the Ezzonid dynasty and – 3rd – Count Palatine Henry of Laach from the House of Luxembourg, predecessor of her son Siegfried.