Regional push derives from the geographic agglomeration of economic activities, and is expressed in increments to national productivity. Various pieces of statistical evidence in favour of the existence of regional push effects in low- and middle-income economies are marshalled. The origins of these effects in different sorts of externalities and increasing returns to agglomerative scale and scope are analysed in theoretical terms. Further evidence for the existence of these effects is displayed in a brief review of published case studies of African, Asian, and Latin American regions. A number of observations are then offered on the possibilities of identifying viable developmental policies and practices directed to enhancing the productivity-boosting properties of regions in low- and middle-income economies.