The role of certitude in our mental lives is, to put it mildly, controversial. Many current epistemologists (including epistemologists of religion) eschew certitude altogether. Given his emphasis on certitude, some have maintained that John Henry Newman was an infallibilist about knowledge. In this paper, we argue that a careful examination of his thought (especially as seen in the Grammar of Assent) reveals that he was an epistemic fallibilist. We first clarify what we mean by fallibilism and infallibilism. Second, we explain (...) why some have read Newman as an infallibilist. Third, we offer two arguments that Newman is at least a fallibilist in a weak sense. In particular, the paradox he seeks to resolve in the Grammar and his dispute with John Locke both indicate that he is at least a weak fallibilist. We close with a consideration of whether Newman is a fallibilist in a much stronger sense as well. (shrink)