Issues about individualism and holism in economics surface because economics is committed to understanding both institutions and large-scale economic processes, in terms of constrained maximizing of individuals. Three key questions are at issue. Can a theory of individual economic behaviour capture everything we want to explain about the economy in principle? To what extent do our accounts of individual economic behaviour trump or constrain other economic explanations that are not directly about individuals? Are non-individual economic entities real, and what is their relation to individual behaviour? These questions are answered in light of developments in economics and in philosophy of science.