Purpose – The governance of information technology outsourcing (ITO) has been identified as an essential determinant for ITO success. Prior studies have shed light on effective governance structures in different organizational contexts. This study aims to advance this prior knowledge by exploring how interpersonal networks, as an important aspect of such context, reflect and influence ITO governance. Design/methodology/approach – A single case study was conducted from a vendor’s perspective in an ITO dyad. Social network analysis was leveraged to reveal the interpersonal networks, with whole-network analysis on 24 team members in an ITO vendor company. In addition, open-ended interviews with six selected team members were utilized to identify the perceived governance structure. Findings – The findings of this study suggest certain features of interpersonal networks, i.e. network density and cross-network comparison, can reflect governance structure in multiple aspects. Meanwhile, the authors also argue that interpersonal networks can influence the form of governance structure. Research limitations/implications – As a single case study, the context of the research site cannot be ignored in the inference of findings. To increase the confidence for further generalization, future empirical studies are needed especially in contrasting sites, such as ITO relations based on network governance. Originality/value – This study associates intra-organizational characteristics of the vendor to the inter-organizational governance structure of the ITO relationship. It also provides an innovative methodology for both researchers and practitioners to assess ITO governance structure.