The emergence of ‘postsecularism’ prompts a re-assessment of the question of Marxism-and-religion, following a long period of polarization then a later twentieth-century phase of ambivalent reticence. But much hangs on whether postsecularism is taken to entail anti-secularism, and whether the latter, though a notable tendency in contemporary social theory, is convincing. The main thrust of this article is to counter two influential strands of theoretical anti-secularism: one drawing on postcolonialist themes and the other headed by Charles Taylor’s now-classic work A Secular Age. My arguments help us to re-specify the atheism-secularism of Marx himself and to identify current options. Singling out for critical note the postsecular positions of ‘compatibilism’ and ‘theologism’, the overall stance that guides the article is that of an expansive intellectual secularism. The point is neither to deny the subjective or political importance of religion nor to underestimate its (variable) societal functionality. Rather, I want to reaffirm an analytical, socio-naturalistic approach to what we understand by religion, and accordingly resist the moralistic, approving tone of many discussions of religion’s ‘revival’. More generally, the cultural, epistemic and imaginative resources of (critically minded) science seem to me still central for social understanding and progressive politics alike, an emphasis that remains one of Marx’s and Engels’ enduring contributions to social thought.