According to a widespread view in metaphysics and philosophy of science (the "Dependence Thesis"), all explanations involve relations of ontic dependence between the items appearing in the explanandum and the items appearing in the explanans. I argue that a family of mathematical cases, which I call "viewing-as explanations", are incompatible with the Dependence Thesis. These cases, I claim, feature genuine explanations that aren't supported by ontic dependence relations. Hence the thesis isn't true in general. The first part of the paper defends this claim and discusses its significance. I argue, for example, that many mathematical explanations are apparently compatible with Dependence, so the existence of counterexamples is interesting and non-obvious. The second part of the paper considers whether viewing-as explanations occur in the empirical sciences, focusing on the case of so-called fictional models (such as Bohr's model of the atom). It's sometimes suggested that fictional models can be explanatory even though they fail to represent actual worldly dependence relations. Whether or not such models explain, I suggest, depends on whether we think scientific explanations necessarily give information relevant to intervention and control.This paper is about a certain mathematical phenomenon, and its implications for a widely held view about the metaphysics of explanation. I'll say more about the mathematical phenomenon shortly. The widely held view is this:Dependence Thesis: All explanations reflect relations of ontic dependence between the items appearing in the explanandum and the items appearing in the explanans.