During the period 2013–2016, the Nordic Working Group for Green Growth: Sustainable Urban Regions (NWG4) and Nordregio have developed and shared knowledge about sustainable urban development, planning and green growth. Working in close collaboration with representatives from ministries and national authorities, policymakers and municipal and regional planners within larger Nordic city-regions, we have identified a number of common challenges and opportunities for sustainable urban development. City-regions are important arenas for addressing the many challenges associated with urban sustainability, inclusiveness and attractiveness. This synthesis highlights some of these key challenges, indicates where there is potential to develop more sustainable and co-ordinated planning and policy-making. It also provides insight into implementation, monitoring and evaluation of various plans and policies through different tools, models and concepts. In addition to outlining common challenges and opportunities for Nordic urban areas and governing city-regions, this report highlights some of the specific national concerns for cityregional planning in Denmark, Finland, Norway and Sweden. It also provides an overview of municipal reforms and regional reforms in the Nordic region as well as an introduction to all the Nordic spatial planning systems. First comes a brief overview of the challenges addressed in this report. The different sections describe these in more depth and contextualising them with relation to the main findings from connected projects carried out by Nordregio. This is followed by national overviews of the spatial planning systems and regional reforms in all Nordic countries, as well as national concerns for city-regional planning. The report is concluded with a section about the NWG4 and a list of the related Nordregio publications.