In Britain, most non-theists and atheists do not identify themselves as such in explicit terms, yet non-theistic cultural threads are interwoven through everyday discourses. This article calls for more extensive ethnographic engagement with these more diffuse—and therefore less visible and less commonly researched—forms of non-religious culture. Based on exploratory fieldwork conducted in South East England, it draws attention to one set of these indistinct non-religious forms: 'authentic' and 'inauthentic' ambivalent atheist and non-religious self-understandings and self-representations. It demonstrates how these identities may be subjectively meaningful and culturally significant and how they may be simultaneously empowering and disempowering. Scrutiny of ambivalent atheist identities points to complicated dynamics between non-religion and power and the value of attending to poorly or unmarked non-religious cultures through ethnographic work.