This project explores a Wittgensteinian framework in epistemology by focusing on religious belief. In particular it concentrates on uses of the concepts of belief, certainty, conviction, doubt, holding for true, knowledge, opinion and proof as they are dealt with in the author’s later thought. Although Wittgenstein himself claimed not to be “a religious man” (yet having a religious point of view upon the world, which most of the times he identified with ethics), he offers us plenty of conceptual instruments for dealing with religious belief. We have selected some specific themes for understanding his grammatical approach as well as its sources and implications. Our starting point is the idea that philosophy of religion is a privileged field to observe the complex relations between Wittgenstein’s early and later thought. From a Tractarian view of epistemology as philosophy of psychology to the remarks on hinge propositions in On Certainty, Wittgenstein’s views of epistemology changed and so did his approach to religious belief. If in the Tractatus Wittgenstein tried to formulate a mystical approach, which he connected with a peculiar form of transcendental solipsism, the mature view on religious belief that we find in the post-1929 writings reveals an author concerned with language as it is employed in our daily lives. In order to understand such change we will consider the idea of a “natural religion”, which exposes, with no theological apparatus, essential aspects belonging to human nature. This is exemplified in the robust criticism of J. G. Frazer’s intellectualist descriptions and interpretations of the rituals of primitive societies. We will also consider the question whether the notion of “form(s) of life” in the Philosophical Investigations, a key for understanding “culture”, is meant as a single one, proper to humanity, or rather as a diversity of “forms of life”. Since the rejection of historicity defended by Wittgenstein in matters of religion is strongly reminiscent of J. H. Newman’s Grammar of Assent, we will look at this text as a possible source for Wittgenstein’s conception of grammar. On Certainty is clearly very rich in implications for an epistemology of religious belief and Duncan Pritchard’s “quasi-fideism”, anchored to the work of the later Wittgenstein, has important implications for understanding the nature of religious disagreements, something that is vital in our contemporary world. Existential scepticism as a threat, from a Wittgensteinian standpoint, will also be explored taking Ernest Sosa’s virtue perspectivism as a reference. Since naturalizing approaches to religious belief carried out under the banner of “naturalism” raise the question of its meaning, we will finally assess how they relate to Wittgenstein’s viewpoint on cultural phenomena. One wider ambition of the project is to defend a Wittgensteinian approach to religion, epistemologically informed, that may open the way to interfaith dialogue.