Inter-organizational collaboration in terms of co-creation, co-development, and co-innovation relies heavily on integrated information systems that support reciprocal relations among member organizations. Ensuring desirable behavior in the use of these inter-organizational IT resources is subject to the emerging research on IT network governance. While past studies have concentrated on singular governance arrangements, there is no study that examines the fit of governance choice and internal and external network factors on governance effectiveness. This paper contributes with a characterization of IT network governance arrangements along the degree of centralization of IT-related decision making. Three archetypes are distinguished: a decentralized mode, a hybrid mode, and a centralized mode. Moreover, a contingency model is developed proposing effective governance arrangements according to six contingency variables. A multiple case study methodology is applied with five case sides for validation. Our data indicate support for both the theoretical archetypes and the contingency model. The results suggest that network size, network structure centralization, functional diversity, network trust, IT infusion, and IT competence are important contingencies for the understanding of effective IT network governance arrangements. This research is a first step into a contingent perspective on inter-organizational IT governance arrangements.