This chapter examines consent in the thought of Thomas Hobbes, John Locke, David Hume, and J.S. Mill across five dimensions: 1) the domain of consent (whose consent is required?), 2) the range of consent (for what sorts of situations is consent relevant?), 3) the characteristics of a legitimate act of consent (under what circumstances is a putative act of consent invalid?), 4) the source of consent’s normative force (why does an act of giving or withholding consent change what is morally acceptable or legitimate?), and 5) the effect of consent (a different moral evaluation? different legal rights? the legitimacy of government?). It concludes by showing how these dimensions have been contested in the quest for equal rights for women.