Recent high-level policy papers call for scaling-up agroforestry to sustainably increase agricultural production and maintain environmental services. Evidence suggests that this will not be achieved by wide scale promotion of a few iconic agroforestry practices. Instead, three key issues need to be addressed. First, fine-scale variation in social, economic and ecological context and how this creates a need for local adaptation. Second, the importance of developing appropriate service delivery mechanisms, markets, and institutional contexts, as well as technologies. Third, appropriate research design, within the scaling process, that enables co-learning amongst research, development and private sector actors. This requires a new paradigm that builds on previous integrated systems approaches, but goes further, by embedding research centrally within development praxis.