This article examines the thesis that rights are always and only conventional rights. It identifies two versions of the conventionalist thesis by distinguishing how each understands a moral right. On one view, a moral right describes a conventional right that ought to exist, irrespective of whether it actually exists; on the other view, a moral right describes an actually existing conventional right that is morally justified. The article criticises both versions of the conventionalist understanding of moral rights and human rights. It also distinguishes the kind of social recognition that contemporary conventionalists insist is a prerequisite for a right from that proposed by T. H. Green. The article concludes with a defence of the orthodox understanding of moral rights and human rights as rights that are moral in foundation and that can be conceived as rights independently of conventional rights.