Agricultural research projects in developing countries focus on modifying farming systems in order to contribute to higher-level development goals such as poverty reduction, food security, and rural development. The success of these projects is tied to the expansion of benefits beyond the projects themselves, that is, scaling out and up. There is significant pressure on research organisations and development actors more broadly to demonstrate the impact of their activities at scale, which is driving a preoccupation with scaling of research findings in agricultural research organisations. Literature on taking research to scale has largely been concerned with stories of technological transfer and spread-identifying which mechanisms best support the dissemination and adoption of new practices by farming households, or how to engage with government departments to embed a new practice in agricultural extension programs. Consideration of scaling processes has been disconnected from broader attention to innovation as a dynamic process influenced by individual, institutional, and political circumstances. The aim of this research was to explore the concepts and assumptions of taking research to scale in agricultural development. The perspective of agricultural innovation systems, which emphasises connectivity and its importance for innovation, was the conceptual starting point. However, this approach has been criticised for failing adequately to consider how these connections can marginalise some actors. Drawing also on political ecology and actor-oriented theory enabled a clearer consideration of diversity, power, structure, and agency to complement the frame provided by agricultural innovation systems. Within this broader framework, the key themes were: history and context; key actors and roles; strategies for scaling research; structure and agency; power and knowledge; and scale and networks. Drawing on analytical perspectives from agricultural innovation systems, political ecology, and actor-oriented theory encouraged critical reflection on how the benefits of new technologies and practices are expanded, and on some of the outcomes of these processes. Three cases of agricultural technology spread were compared: higher-yielding rice varieties in Laos; small-scale agricultural machinery in Thailand; and improved cattle management in Indonesia. Cases featured different social and political systems, different types of technology, different degrees of 'success', and different mechanisms for scaling. The case studies draw on interviews with key actors, project documents, evaluations, and reports to explore how the intersection of key actors, networks, and events influenced efforts to expand project impact. iii The cases highlight that the narratives and expectations around scaling are often oversimplified , reinforcing a focus on binary adoption of research-driven technology, and are unable to account for the complex array of actors, motivations, and ongoing learning processes that underpin efforts to take research to scale...