Neo-institutionalism has had a deep impact on the economic study of antiquity, to the point where it has become the de facto scholarly default. But although it has been beneficial to analyses of discrete ancient economies it has yet to be employed to study the overall economic performance of the Greco-Roman world. The ancient Mediterranean seems to have experienced long-term trends of growth and contraction that transcended traditional chronologies, as suggested by archaeological data. Those data increasingly point to the need for an encompassing economic narrative. Neo-institutionalism holds the promise of facilitating such a narrative, while avoiding the formalist/substantivist debate of the previous decades. A neo-institutional research agenda will allow scholarship to approach the question of what produced both the success and failure of the economies of the ancient world in the aggregate.