R.M. Hare had an ambitious scheme of providing a unified account of meta-ethics and normative ethics by combining expressivism with Kantianism and utilitarianism. The project of this thesis is to defend Hare’s theory in its most ambitious form. This means not just showing how the expressivist, Kantian and utilitarian elements are consistent, or that the three are each correct, but also that they are interdependent. The only defensible form of expressivism is Kantian; the only defensible Kantian theory is both expressivist and utilitarian; the only defensible utilitarianism is Kantian. The thesis is divided into four chapters. Chapter 1 aims to show how expressivism can provide a coherent account of moral judgement and discourse. The argument for expressivism draws on Hare’s thought that the main error of moral realism is to think of moral objectivity as requiring objects, moral properties which are really there in the world. It is shown, using an argument based on the Euthyphro and the Open Question Argument that realism is untenable because it makes this mistake, and this clears the path to expressivism. Chapter 2 is a full account of the issues surrounding the Frege-Geach problem (often pressed against Hare), showing how it can be solved and how exactly the expressivist’s embrace of minimalism about truth interacts with the solution to the Frege-Geach Problem. I include an explanation of how the expressivist is able to solve the most threatening version of the problem: Schroeder’s discussion of negation. Chapter 3 argues for the connection between expressivism and Kantianism. The argument (roughly following Korsgaard) is that Humean versions of expressivism run into a sceptical challenge of normative regress. Kant employed a transcendental argument to resolve this regress, deriving his Formula of Universal Law from the Categorical Imperative. This argument defended with expressivism playing a crucial role. This chapter thus explains how Hare is entitled to universalizability in a way that avoids the shmoralising objection: it is not justified merely by being derived from our moral concepts but rather from our inescapable nature as agents. Chapter 4 illuminates the other connection, between Kantianism and utilitarianism. The largest part of the chapter is spent defending Hare’s argument from universalizability to utilitarianism. Doing so shows how Hare’s utilitarianism depends on his Kantianism, and so also how it indirectly depends on his utilitarianism. I then go on to defend Hare’s distinctive two-level version of utilitarianism, especially against the objections of Bernard Williams. It is also argued that various difficulties for utilitarianism – utility monsters, interpersonal comparison, Korsgaard’s objections – can be met by a form of utilitarianism like Hare’s, which is Kantian, and thus that such a form of utilitarianism is indeed the most defensible.