How to minimize risks involved in enterprise systems (ES) implementation while maximizing benefits has become a challenge for top management. This article proposes a conceptual model exploring impacts of top management on ES implementation effectiveness. This paper takes a perspective of innovation implementation because of the fact that ES, per se, is an IT innovation. This paper addresses ES implementation issues through its focus on two research questions: 1) what influences does top management exercises on the ES implementation? and 2) what top management contributes to a successful ES implementation under different implementation modes? Based on Klein and Sorra’s (1996) model, this paper develops a research model and identifies three top management influences to explore these research questions. The paper concludes with potential contributions to IS researchers and business practitioners.