Recent initiatives by Stein, Flynn, Conrad, and others have promoted ‘unbelief’ as a replacement, an ‘umbrella term,’ for concepts like atheism, secularism, and irreligion. In this essay I show that unbelief as it is currently construed cannot serve this function: it is simultaneously too broad (embracing not only irreligion but heterodox religious belief) and too narrow (focusing on religious belief to the exclusion of other types of belief), and it commits a taxonomic error of equating unbelief with categories above and below its level. However, I also argue that, once reformed and disciplined, unbelief is a valuable and essential tool, and I provide some resources and models for a future Unbelief Studies in the Credition Research Project and the literature on agnotology, as well as ethnographical material questioning the cross-cultural applicability of belief and unbelief. Finally, I charge Unbelief Studies with the mission not only to analyze belief but to criticize and ultimately banish it as a bad mental and linguistic habit that perpetuates mistakes and leaves individuals vulnerable to further faults while eroding social trust and facticity itself.