Regional institutional integration is viewed by many as an essential precursor to the achievement of rural sustainability in that it addresses increasing concerns about institutional complexity in rural areas and the need to manage ecosystems at a bioregional scale. Governments are requiring planners to engage citizens, organizations, and institutions in regional strategic planning, regional organizational amalgamation, and regional administrative-boundary reconfiguration to achieve such integration. Despite this popularity, these approaches still are not well thought out. In particular, there has been little critical hypothesis development on institutions and regional integration by which planning practice toward achieving rural sustainability can be guided. This article seeks to show how certain elements of the scholarship in a range of disciplines within and outside planning can shed light on the different dimensions of this concept. This review enables important lessons to be drawn for planners, citizens, and governments concerned with institutions, integration, and the environment.