A reasonable distribution of urban systems is essential for optimizing spatial energy allocation and the quality of economic growth for China. This study discusses the impact of the polycentric development on the regional gap of energy efficiency (RGEE), i.e. difference in energy efficiency levels among cities in the same region, in the Chinese provincial context, by employing a novel method using nighttime lighting data from Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) to measure the spatial structure of provinces and Stochastic Frontier Approach (SFA) to evaluate the total-factor energy efficiency. Our results firstly show that the polycentric development has a narrowing effect on the RGEE. Second, they show that the more government intervention can narrow the RGEE of a province, but being more open, having more foreign direct investment (FDI), and using more coal can widen the RGEE of that province. Meanwhile, the level of regional urbanization is shown to have no influence on RGEE. Third, they show that the polycentric development has a negative effect on the energy efficiency of large cities, but a positive effect on that of small and medium size cities, which accordingly narrows the RGEE. The conclusions of this study not only reveal insights for policies that aim to reduce the RGEE, but also provide an empirical basis for future urban development strategies in the Chinese provincial context.