Social Requirement Theory is the view that moral obligations are reasons for action constituted by the actual demands of an agent's culture. These demands constitute practical reasons in virtue of being backed by threats of censure or ostracism for noncompliance, and they obligate only agents whose desires or interests are served by avoiding such consequences. This stance is best construed as a version of realism about moral obligation since the reasons in question are as real as any practical reasons could possibly be; but the mind-independence versions of realism that most interest philosophers are of little practical relevance. Mark Kalderon's recent arguments for moral noncognitivism are flawed. And contra Richard Joyce's recent argument for moral error theory, moral obligations need not be strictly metaphysically necessary to satisfy our prephilosophical intuitions about morality's inescapability. Social Requirement Theory is form of agent relativism and compares favorably to other contemporary moral relativisms, such as those of Gilbert Harman, David Wong, and James Dreier. As an actual-demand theory, it is similar to Robert Adams's divine command theory but enjoys several advantages over the latter while still allowing a substantial role for God in the moral life.