The idea of moral progress played a central role in liberal political thought from the Enlightenment through the nineteenth century but is rarely encountered in moral and political philosophical discourse today. One reason for this is that traditional liberal theorists of moral progress, like their conservative detractors, tended to rely on under-evidenced assumptions about human psychology and society. For the first time, we are developing robust scientific knowledge about human nature, especially through empirical psychological theories of morality and culture that are informed by evolutionary theory. On the surface, evolutionary accounts of morality paint a rather pessimistic picture of human moral nature, suggesting that certain types of moral progress are unrealistic or inappropriate for beings like us. Humans are said to be ‘hard-wired’ for tribalism. However, such a view overlooks the great plasticity of human morality as evidenced by our history of social and political moral achievements. To account for these changes while giving evolved moral psychology its due, we develop a dynamic, biocultural theory of moral progress that highlights the interaction between adaptive components of moral psychology and the cultural construction of moral norms and beliefs, and we explore how this interaction can advance, impede, and reverse moral progress.