Policies and plans for resource and environmental management are needed, but if not implemented, or implemented poorly, their value is reduced. Experience suggests that we often struggle to achieve effective implementation. In this chapter, the implementation gap is examined, with the aim being to identify what are known expectations for successful implementation of policies and plans, which obstacles frequently hinder implementation, and what capacity is required for effective implementation. Subsequently, the difference between programmed and adaptive implementation is examined, followed by discussion of the role of different partnership and stakeholder arrangements to facilitate implementation. Detailed case studies of coastal management in Japan and of water policy implementation in the São Paulo state in Brazil provide further insights. Bakti Setiawan and Dwita Rahmi, in their guest statement, review the role of bureaucracy, politics, and leadership in establishing a protected agricultural area in Yogyakarta, Indonesia.