Reformed Churches, those Protestant churches following the doctrines and polity of the Protestant reformers Huldreich Zwingli and John Calvin rather than the Lutheran tradition. Calvin's influence proved even more powerful than that of Zwingli. Throughout Europe the Reformed Churches became known as Calvinistic churches, the name Protestant church in some countries being almost equivalent to Lutheran. One chief distinction of the Reformed churches is their doctrine of the Eucharist, characterized by the rejection of both transubstantiation (Roman Catholic) and consubstantiation (Lutheran). A memorial view of the sacrament is held. They also reject certain ceremonies that the Lutherans retain.

The Alliance of Reformed Churches Throughout the World Holding the Presbyterian Order is an organization formed in London in 1875 to encourage comity, cooperation, and efficiency in Christian work. About 110 churches in the United States and many in Europe belong to the Reformed rather than the Lutheran tradition.