Adalbero of Würzburg (or Saint Adalbero) (c. 1010 – 6 October 1090) was Bishop of Würzburg and Count of Lambach-Wels.
He was the son of Count Arnold II of Lambach in Upper Austria (of the family of the Counts of Formbach) and his wife the Countess Reginlint. He was born around 1010 in Lambach an der Traun. After his studies in the cathedral school at Würzburg Adalbero entered the service of King Henry III, who in 1045 nominated him as successor to Bruno as Bishop of Würzburg.
Bishop Adalbero continued the construction of the new cathedral begun by Bruno and established the "Neumünsterkirche" ("New Minster Church") (built between 1058 and 1063). Significant contributions in the reform of ecclesiastical life are attributed to him. He was in close contact with the reformers at Cluny, Gorze and Hirsau. He brought the monk Egbert from Gorze, who proved extremely effective firstly in bringing about the renewal of Münsterschwarzach Abbey and then, through the spread of the subsequent Münsterschwarzach Reforms, in exerting an influence far beyond it, from Harsefeld Archabbey near Stade in the north to Melk and Lambach (a reformed Benedictine abbey founded by Adalbero himself in the castle of his family) in the south. In 1057 Adalbero re-settled the abbey of St. Peter, Paul and Stephen in Würzburg, until then a college of canons regular, with Benedictines from Münsterschwarzach.
After the death of Henry III, Adalbero intensified his involvement in the councils of the empire and the court and in synods, and gained a reputation as an advisor and mediator. In 1066 in Würzburg he performed the marriage ceremony between Henry IV and Bertha of Savoy. Together with other princes he brokered the Peace of Speyer in 1075.