National development planning processes must consider the environment if sustainable development is to be ensured. But the capacity for greening these processes is often lacking in developing countries. This chapter outlines the legal and political context and the key actors involved in national planning processes. It then draws on the five-step framework to provide guidance on building the capacity for greening these planning processes. Case studies illustrate how capacity development has allowed environmental issues to be incorporated into national planning processes in a variety of developing countries.