The paper focuses on Priestley’s complex views on the essence of God in connection with his materialism, elaborated in the Disquisitions Relating to Matter and Spirit (1777/ 1782). This issue is crucial if one wishes to get a clear idea of what Priestley’s materialism amounts to; whether it is mainly a thesis about the material grounds of the human mind (“psychological materialism”), or a more far-reaching one about what kind of substances exist in the world (a version of “ontological materialism”). (...) The claim that God may be material allows for the most radical version of ontological materialism according to which everything in the world is material, without altogether denying that God exists. In fact, Priestley considers and partially defends at least three different views on the potential materiality of God: (1) an agnostic stance that is his official view, (2) materialism about God based on his own theory of matter, and (3) “gross” materialism about God. The aim of the paper is to analyze these three views, in particular concerning what kind of materialism they support and whether they can contribute to the consistent Christian materialism Priestley envisaged. (shrink)