The objective of this chapter is to investigate the implementation of National Sustainable Development Strategies (NSDSs) at the sub-national level in selected European Union (EU) member states. The focus is on the governance arrangements and policy priorities to promote sustainable development at the regional level. Key policy issues for the promotion of sustainable development, for example, climate change and biodiversity, cross-cut not only the horizontal boundaries between various central government ministries, but also the vertical levels of political systems. Thus, it is important to examine the vertical dimension of policy-making if we are to fully understand the relevance and impacts of sustainable development strategies and policies. By exploring conceptual and practical approaches towards vertical policy integration in the context of NSDSs, this chapter tries to capture the ‘steering capacity’ of the nation state in pursuit of sustainable development.