Cities are vital for achieving the Sustainable Development Goals (SDGs), but different local strategies to advance the same SDG may cause different “spillovers” elsewhere. Research efforts that support governance of such spillovers are urgently needed to empower ambitious cities to “account globally” when acting locally on SDG implementation strategies.

However, there are a number knowledge gaps in research related to cities’ spillovers, which require urgent attention for two reasons. First, cities’ actions are often atypical of their country contexts and many decisions that influence global development are made at this subnational level. Second, since most cities’ work to achieve the SDGs still lies ahead, there is an urgent need to increase the ability to predict and manage the spillovers of their future sustainability actions.

This article explores the challenges of accounting for cities’ spillovers and outlines a number of priorities for integrating spillover considerations into city-level SDG strategies.