Management support is considered to be a critical factor in the successful implementation of information systems innovations. The literature suggests a complex relationship between management support and implementation success. However, the empirical literature typically hypothesizes and tests a simple main-effects model. Drawing upon the role of the institutional context and metastructuration actions, we propose a contingent model in which task interdependence moderates the effect of management support on implementation success. A meta-analysis of the empirical literature provides strong support for the model and begins to explain the wide variance in empirical findings. Implications for theory and practice are discussed.