Two kinds of metaphors used by Leibniz in Theodicy are of particular philosophical interest: explicit metaphors introduced by ‘like’, ‘similar to’, etc., and metaphors featuring mathematical entities or procedures as terms of comparison. Both kinds are relevant to our understanding of the relation between metaphoric reasoning and more formal argumentations. I argue that they should be distinguished, for practical reasons, from allegories, which are also present but have different structure and functions. My focus is especially on the following Leibnizian metaphors: the recurring declaration that essentiae rerum sunt sicut numeri, erroneously considered as a Pythagorean or Platonic saying, whereas it is a traditional tenet of Aristotelianism; the calculus de maximis et minimis, a family of comparisons recurring in Leibniz’s works; geometry, variously declined; and the famous comparison of possible worlds and their ramifications to the loci geometrici of points.