Proponents of the harm principle often appeal to a notion of personal sovereignty in setting out their position. This notion helps to fix the application of the harm principle. Critics of the harm principle seize on this point and argue that, once a principle of sovereignty is introduced, it can do all the work that needs doing. Appeals to harm become otiose. Further, the critics contend, the harm principle cannot explain the impermissibility of certain “harmless” wrongs, such as those involved in harmless trespass. This chapter assesses this sovereignty-centered critique of the harm principle. It argues that neither the harm principle nor the sovereignty principle enjoys priority over the other. The two principles complement each other with neither meriting a privileged position. The chapter then discusses the content and stringency of the sovereignty principle, and its relation to the Volenti Maxim, which holds that a person is not harmed or wronged by that to which they consent. The critical discussion of the Volenti Maxim, in turn, reveals limits to the sovereignty principle.