Matthäus Lang von Wellenburg (1469 - 30 March 1540) was a German statesman and archbishop of Salzburg.

He was the son of a burgher of Augsburg and afterwards assumed the name of Wellenburg from a castle that came into his possession. After studying at Ingolstadt, Vienna and Tubingen he entered the service of the emperor Frederick III and quickly made his way to the front. He was also one of the most trusted advisers of Fredericks son and successor Maximilian I, and his services were rewarded in 1500 with the provostship of the cathedral at Augsburg and in the following year with the bishopric of Gurk. In 1511 he was made a cardinal by Pope Julius II, and in 1514 he became coadjutor to the archbishop of Salzburg, whom he succeeded in 1519. He also received the bishopric of Cartagena in Murcia in 1521, and that of Albano in 1535.

Lang's adherence to the older faith, together with his pride and arrogance, made him very unpopular in his diocese of Salzburg; in 1523 he was involved in a serious struggle with his subjects, and in 1525, during the Peasants War , he had again to fight hard to hold his own. He was one of the chief ministers of Charles V; he played an important part in the tangled international negotiations of his time; and he was always loyal to his imperial masters. Not without reason has he been compared with Cardinal Wolsey.