Christine Korsgaard has attempted to defend a distinct approach to metaethics – Neo-Kantian Constructivism. Not only does she present a positive case for her own view, she also attacks existing metaethical positions and even the disctinctions that metaethics has traditionally relied on. This thesis is a sustained examination of this position. I consider whether Korsgaard can legitimately claim to be offering a metaethical position at all, providing her with some defence against the scepticism of some metaethicists. I also examine her (...) attacks on traditional metaethical positions. I argue that her attack on moral realism can be avoided if the realism on offer takes a particular form. In the case of expressivism I claim that Korsgaard’s attack, though not fully developed in her work, motivates an examination of contemporary hybrid-expressivist theories. I argue that these are, as of yet, no advance over their non-hybrid cousins. Finally I examine Korsgaard’s own position, attempting to make it clearer by combining her claims with a framework developed by Crispin Wright for judgement-dependent qualities. This gives Korsgaard her best chance of a distinctive metaethical position. Ultimately, though, the Neo-Kantian approach to morality fails. (shrink)