Purpose – This paper aims to address the gap that, to date, no systematic review has been carried out on the role that structural social capital (SC) plays for knowledge transfer and innovation at the interpersonal, inter-unit and inter-firm levels. Individuals and organisations are becoming increasingly involved in collaboration networks to share knowledge and generate innovation. SC theory has been adopted in several areas of study to explain how individuals, groups and organisations manage relationships to generate innovation. Design/methodology/approach – This review covers studies of SC in organisational behaviour, strategy and management over a period of 20 years. Findings – The literature review shows that knowledge types and knowledge transfer processes are the missing links in the relationship between structural SC and innovation. Moreover, the paper demonstrates that seemingly opposite configurations of SC are complementary to each other (structural holes vs dense networks; strong vs weak ties) and that contextual factors should be considered when discussing the effects of SC on knowledge transfer and innovation. In addition, it is the balance of different configurations of SC which enables an individual or a company to explore, access, assimilate and combine different knowledge types, which will lead to improved innovation outcomes. Originality/value – This review facilitates understanding of the role of SC for knowledge transfer processes and the mediating role of knowledge transfer processes and knowledge types in the relationship between structural SC and innovation.