With its distinctive emphasis on God’s sovereignty, the theological and ecclesiastical tradition called “Reformed” resists a sharp separation between theology and politics or economics, although it carefully distinguishes them. Reformed thinking about taxation reflects a concern to use tax, especially in light of Romans 13:1–7, as a model for understanding the sources of divine authority for the civil community. In different language but using similar concepts, Reformed theologians such as Huldrych Zwingli, Heinrich Bullinger, Martin Bucer, John Calvin, Theodore Beza, Peter Martyr Vermigli, Girolamo Zanchi, Francis Turretin, Johannes Althusius, John Knox, Samuel Rutherford, Abraham Kuyper, Reinhold Niebuhr, and Karl Barth sought to clarify the theological significance of tax and, with it, the civil realm and the creation order. Two primary themes emerged: (1) natural law rather than scripture supplies the principles that govern Christ’s reign as creator over the earthly kingdom; and (2) the wall of separation between that reign and Christ’s rule as redeemer over the spiritual kingdom is porous, allowing influences to run from one realm to the other. In Reformed political theology, taxation is a prominent instrument for achieving a practical adjustment of the conflicting norms prevailing in each realm.