Previous research has alluded to the predominance of atheism in participant pools of the Nonhuman Animal rights movement (Galvin and Herzog 1992; Guither 1998), as well as the correlation between atheism and support for anti-speciesism (Gabriel et al. 2012; The Humane League 2014), but no study to date has independently examined this demographic. This article presents a profile of 210 atheists and agnostics, derived from a larger survey of 287 American vegans conducted in early 2017. Results demonstrate that atheists constitute one of the movement’s largest demographics, and that atheist and agnostic vegans are more likely to adopt veganism out of concern for other animals. While these vegans did not register a higher level of social movement participation than religious vegans, they were more intersectionally oriented and more likely to politically identify with the far left. Given the Nonhuman Animal rights movement’s overall failure to target atheists, these findings suggest a strategic oversight in overlooking the movement’s potentially most receptive demographic.