The outsourcing of information technology (IT) to external vendors promises lower delivery cost while attaining higher delivery quality. Despite these positive prospects, many information technology out-sourcing (ITO) projects still fail, often due to an unsuccessful client-vendor relationship. Most research to date has focused on investigating this relationship from the clients’ perspective, even though the vendor is equally important for success. This study empirically identifies 65 vendor-focused factors influencing the development and maintenance of a successful ITO client-vendor relationship by applying Kelly’s personal construct theory and the corresponding repertory grid (RepGrid) method. All factors were thoroughly analyzed and categorized based on an a priori conceptual framework for interorganizational relationships derived from organizational exchange theory. The analysis of the identified fac-tors yielded client organization specifics such as top quality client team members, client involvement as well as client team member’s networks as especially important for ITO relationship success from the perspective of the vendor, while identifying age of relationship and prior experience with similar projects as less essential compared to prior studies on this topic from a client perspective. With our results, we shed light on the as-of-yet under-researched perspective of the vendor’s needs in ITO relationships and we provide indications for gaps in our knowledge on this important topic.