The exploration of the impact of religiosity on mental health is an enduring, if somewhat quiet, tradition. There has been virtually no exploration, however, of the influence of atheism on mental health. Though not a “religion,” atheism can be an orienting worldview that is often consciously chosen by its adherents, who firmly believe in the “truth” of atheism—a phenomenon known as “positive atheism.” Atheism, especially positive atheism, is currently enjoying something of a renaissance in the Western liberal democracies—a trend often referred to as the “new atheism.” I argue that atheism, especially positive atheism, should be treated as a meaningful sociocultural variable in the study of mental health. I argue that atheism (just like theism) is an appropriate domain of study for social and cultural psychiatrists (and allied social scientists) interested in exploring socio-environmental stressors and buffers relating to mental health. Specifically, I argue that (1) atheism needs to be accurately measured as an individual-level exposure variable, with the aim of relating that variable to psychiatric outcomes, (2) there needs to be greater systematic investigation into the influence of atheism on psychiatry as an institution, and (3) the relation of atheism to mental health needs to be explored by examining atheistic theory and its practical application, especially as it relates to the human condition, suffering, and concepts of personhood.