The sustainable intensification of agriculture to achieve food security is a complex challenge that requires technological and institutional change. The Agricultural Innovation Systems (AIS ) concept is a strategic framework that takes a demand-driven, interactive approach to innovation in agriculture. This report establishes the concept of the capacity to innovate, which depends not only on hard technical capacities, but also softer functional capacities across the individual, organizational, a nd enabling environment scales. It argues that developing country-level innovation capacity requires an iterative capacity development process based around assessment. After reviewing the relevant assessment methods and tools, a general framework for assessing the capacity to innovate is proposed and applicable tools are suggested that explore key areas that influence the capacity to innovate. Tailored to specific situations, this framework can enable a systemwide assessment process that guide i nterventions to develop and sustain the capacity to innovate in order to achieve sustainable food security.