Information systems (IS) have become a vital component of an organization's competitive practices. Organizations have tried to differentiate themselves based on their use and adaptation of new information technology. Top management support (TMS) is a significant factor in influencing the effectiveness of the IS function in an organization. The literature has conceptually supported this notion, but empirical evidence has been sparse. This paper develops a two-tiered framework for studying the relationship between top management support, the IS function, and IS performance. This conceptual model was empirically tested using structural equation modeling based on data collected through a survey instrument. The results support the direct and indirect relationships depicted in the model between top management support and IS performance.