Abstract Understanding the research–policy nexus in developing economies requires knowing who disseminates and how social science research (SSR) is diffused. Based on survey and secondary data on a diverse set of critical stakeholders, this paper characterises the SSR diffusion landscape in Nigeria. We find that university researchers are the most active disseminators of SSR though other actors also engage in dissemination activities. Collaboration among different categories of actors, both locally and internationally, is pervasive in the system. However, online visibility of research is poor in the Nigerian SSR system. Most of the local scientific journals do not operate online, and a large share of the published SSR output is missing from widely used bibliographic databases. For a better research–policy nexus, research producers need to become skilled research advocates and policymakers need to be accessible to other actors.