ABSTRACT Overcoming fragmentation by strengthening the functional coherence of megaregions is deemed essential to reaping the benefits associated with megaregions. However, few studies have examined whether planned megaregions are functionally coherent. We assess the functional coherence of megaregions from three dimensions: inclusion, integration and consistency. Fifteen government-defined Chinese megaregions are evaluated and qualified. For nine of these cases, our analysis reveals discrepancies with the government’s defined development level. Our approach allows one to identify which dimension of megaregional functional coherence needs targeted policy attention to further develop megaregions and can be implemented to explore other megaregions across the world.