Konrad Grebel (c. 1498–1526) was a Swiss humanist and one of the principal founders of the Anabaptist movement. Born into an influential family in Zurich, he studied in Basel, Vienna, and Paris before joining the reform efforts surrounding Ulrich Zwingli. Grebel later became a leading advocate of believers’ baptism and helped shape the early Anabaptist traditio. In English-language sources, his first name is commonly spelled Conrad with a C, rather than Konrad with a K.