 The term ‘contractualism’ can be used in a broad sense—to indicate the view that morality is based on contract or agreement—or in a narrow sense—to refer to a particular view developed in recent years by the Harvard philosopher T. M. Scanlon, especially in his book What We Owe to Each Other. This essay takes ‘contractualism’ in the narrower sense. We begin with a brief summary of Scanlon’s contractualism, and then situate his view in relation both to other social contract theories and to its main rival among impartial accounts of morality—namely, utilitarianism. Our discussion is then organised around a series of challenges to the contractualist account.