This article affirms the importance of ecclesiastical polity as a theological–juridical discipline and explores its connection to ecclesiology and church law. It argues that the Anglican Communion, though not itself a church, nevertheless has a lightly structured ecclesiastical polity of its own, mainly embodied in the Instruments of Communion. It warns against short-term, pragmatic tinkering with Church structures, while recognising the need for structural reform from time to time to bring the outward shape of the Church into closer conformity to the nature and mission of the Church of Christ. In discussing Richard Hooker's contention that the Church is a political society, as well as a mystical body, it distinguishes the societal character of Anglican churches from the traditional Roman Catholic conception of the Church as a societas perfecta. In the tradition of Hooker, the role of political philosophy in the articulation of ecclesiology and polity is affirmed as a particular outworking of the theological relationship between nature and grace. The resulting method points to an interdisciplinary project in which ecclesiology, polity and church law, informed by the insights of political philosophy, serve the graced life of the Church in its worship, service and mission.