Kohlberg’s claim that his theory of moral reasoning development has universal validity and that the evidence is consistent with a position of ethical nonrelativity is evaluated. The available data indicate that the cognitive-developmental criteria for a strict moral stage model do hold universally and that the theory does reflect much of what is morally relevant in diverse cultures. However, the theory’s universal applicability is challenged by evidence that it misses or misconstrues some significant moral concepts from several cultures. It is argued that Kohlberg’s universality claims are grounded in metaethical assumptions about the nature of morality. Although the validity of these assumptions cannot be proven at an empirical level, doubt would be cast on their plausibility by failure to support the empirical claims of the theory.