Inheritors of the Calvinist Reformed tradition have long disagreed about whether knowledge of God’s nature and existence can be or need be acquired inferentially by means of the standard arguments of natural theology. Nonetheless, they have traditionally coalesced around the thought that some sense or awareness of God is naturally implanted or innate in human beings. A root of this orientation can be found in John Calvin’s discussion of the sensus divinitatis in the first book of The Institutes of the Christian Religion. This paper outlines a pedagogical strategy for organizing and evaluating Calvin’s treatment of the sensus divinitatis, chiefly by putting it in tension with John Locke’s polemic against innatism in Book I of An Essay concerning Human Understanding. I begin by reconstructing Calvin’s depiction of the sensus divinitatis, as well as his case for thinking that it is innate. I then explain how Locke’s critique of innatism offers a fairly direct response to Calvin and, hence, a useful framework for exploring the limits of Calvin’s treatment of the sensus divinitatis.