Among the available metaethical views, it would seem that moral realism—in particular moral naturalism—must explain the possibility of moral progress. We see this in the oft-used argument from disagreement against various moral realist views. My suggestion in this paper is that, surprisingly, metaethical constructivism has at least as pressing a need to explain moral progress. I take moral progress to be, minimally, the opportunity to access and to act in light of moral facts of the matter, whether they are mind-independent or -dependent. For the metaethical constructivist, however, I add that moral progress ought also mean that agents come to be or could come to be motivated to act in light of the right kind of moral judgments. Together I take this to mean that, for all forms of constructivism, moral progress must be explained as a form of moral improvement, or agents aspiring to be better sorts of moral agents. In what moral improvement consists differs for various forms of constructivism. Here I distinguish between three different versions of metaethical constructivism: Humean constructivists as represented by Street, Kantian constitutivist constructivists as represented by Korsgaard, and constructivists about practical reason as represented by Carla Bagnoli. I conclude by showing that only constructivism as a view about practical reason can fully account for moral progress qua the opportunity for moral improvement.