This paper presents and discusses a diagnostic framework to identify institutional processes in the creation of public-private partnerships (PPPs) for agricultural innovation. The diagnostic framework proposed here combines a conceptualisation of institutions with a conceptualisation of technology. We argue that a performative notion of institutions provides a better tool for institutional diagnostics than the common understanding of institutions as 'rules of the game'. The paper furthermore proposes to conceptualise technology as affordance, in contrast to a more common understanding of technology as an input. We explore the value of our diagnostic framework by analysing the literature on PPPs for agricultural innovation and unpublished data from a PPP initiative for smallholder sorghum production, based on an agreement between Uganda's National Agricultural Research Organisation (NARO) and Nile Breweries Limited (NBL). In the discussion and conclusion section we evaluate the benefits of our diagnostic framework and discuss how the empirical issues it brings forward create important lessons for analysis of innovation for African smallholder farming and institutional diagnostics more generally.