Aside from some attention to the notion of material falsity that Descartes cites, Francisco Suárez’s broader discussion of falsity in Metaphysical Disputations 9 has received little scholarly attention. This chapter takes a broader look, starting with Suárez’s claim that falsity, unlike truth, is properly attributed only to intellectual acts of composition and division, before focusing on the question of where false judgements or errors come from. Suárez considers several possible sources—God, an evil angel, apparent evidentness—that might make us form false judgements, but argues that none of them actually necessitate false judgements. In line with his doxastic voluntarism, Suárez concludes instead that our wills are the source of our errors. We voluntarily assent to false propositions (though in a different work, Suárez seems more open to recognizing involuntary error). The similarity between Suárez’s account of error and Descartes’ later account is easy to see.