ABSTRACTWe analyse the determinants of local government efficiency taking into account the presence of spatial interactions among neighbouring municipalities. To do so, first we estimate an efficiency index using the robust order-m methodology in Valencian municipalities (Spain). Second, we examine the socio-economic, political and budgetary factors that might influence efficiency levels. Finally, we analyse the spatial interactions present in our data. The results of estimating a spatial autoregressive model show that government efficiency in neighbouring municipalities positively affects the local government’s own efficiency. This highlights the importance of considering spatial dependence structures in studies on efficiency in the public sector.