Andreas Karlstadt, Christian theologian and reformer (born 1486)
Andreas Rudolph Bodenstein von Karlstadt (1486 – 24 December 1541), better known as Andreas Karlstadt or Andreas Carlstadt or Karolostadt, or simply as Andreas Bodenstein, was a German Protestant theologian, University of Wittenberg chancellor, a contemporary of Martin Luther and a reformer of the early Reformation.

Karlstadt became a close associate of Martin Luther and one of the earliest Protestant Reformers. After Frederick III, Elector of Saxony concealed Luther at the Wartburg (1521–1522), Karlstadt and Thomas Müntzer started the first iconoclastic movement in Wittenberg and preached theology that was viewed as Anabaptist, but Karlstadt and Müntzer never regarded themselves as Anabaptists.

Karlstadt operated as a church reformer largely in his own right, and after coming in conflict with Luther, he switched his allegiance from the Lutheran to the Reformed camp, and later became a radical reformer before once again returning to the Reformed tradition. First, he served as one of many Lutheran preachers in Wittenberg. He travelled widely, but only within the borders of the Holy Roman Empire, visiting German-speaking, French-speaking and Italian-speaking lands. By the end of his life he had allied himself with Heinrich Bullinger in Switzerland and worked in Basel, where he eventually died. Despite coming closer to the Reformed tradition by the time of his death, Karlstadt maintained his own distinct understanding on many theological issues throughout much of his life.