Collaborative projects are increasingly common today and such projects require specialized knowledge of the partners to be integrated, therefore posing the challenge of inter‑organizational knowledge integration; integrating diverse knowledge bases across organizations. Studies on knowledge integration and inter‑organizational networks indicate the positive influence of social capital in the context. Since partners in a collaborative project are likely to possess this resource due to their partnership, a knowledge integration view is adopted to conduct an empirical investigation of a three‑partner collaborative project to investigate the influence of social capital. The study shows how the different aspects of social capital influence the knowledge integration behaviour of the partners for the project. Implications to research and practice are discussed.