This article contributes to the emerging body of knowledge on the role of the private sector in knowledge brokering in international development because very little is known about the role of the private sector. It attempts to validate the findings of the only literature review to date (Kiwanuka et al, In Press) on the subject and other literature on knowledge brokering by consulting international experts in the field of knowledge brokering, identifying policy and research implications. The conceptual lens employed is the ‘extended’ Glegg and Hoens’ (2016) meta-framework of knowledge brokering, in combination with the cognitive, relational and structural aspects of social capital (Nahapiet and Ghoshal 1998). An online questionnaire survey was distributed to international experts in both the private, public and civil society sectors with some 203 respondents. The questions were developed on the basis of the literature. Respondents from the private sector and their colleagues from the public sector and civil society placed considerable emphasis on opportunities to meet, the existence of personal relationships and brokering by third parties as catalysts to working with the private sector. In addition to developing recommendations for policymakers, the paper has added to the emerging body of academic knowledge on the private sector as an unusual suspect in knowledge brokering and provides a conceptual framework linking social capital to knowledge brokering roles. Policymakers and funders can facilitate cooperation between the private sector and other development actors by creating physical spaces and funding instruments to encourage collaboration with the private sector. One of the novel findings is that the public sector needs to be better prepared to collaborate with the private sector.