Claims of voluntariness and the converse notion of force are invoked as the bases for conclusions about people’s rights and responsibilities in a wide range of contexts. Yet the notion of voluntariness has received less direct attention than have the related notions of freedom, coercion, autonomy, and self-ownership. The aim of this chapter is to bring to light and assess the distinctive role and normative significance of voluntariness for our judgments about people’s rights and obligations. In particular, the chapter addresses two main questions about the relevance of voluntariness. The first is whether voluntariness itself, or only the absence of coercion, has normative significance. The second is whether the notion of self-ownership must be defined through voluntariness, and what implications this has for the theses that political philosophers make by appealing to the importance of self-ownership.