ERP assimilation involves both strategic levels and individual level. Focusing on either micro or a macro stance yields an incomplete understanding of behaviour occurring at either level. The main objective of this research is to bridge across different levels of analysis in understanding ERP assimilation. First built upon the existing experiences with ERP software application and prior research, we conceptualize ERP assimilation to be multilevel, including three dimensions of ERP assimilation across different organizational levels, i.e., strategic level, activity level, and individual level. Drawing upon Institutional theory and empowerment theories, we integrate macro and micro approaches to develop a multilevel model explaining ERP assimilation. Top management championship and empowerment climate are proposed to be factors influencing ERP assimilation in corporate strategies and value-chain activities; while psychosocial empowerment is the main driving force for individual ERP assimilation and satisfaction with ERP. Empowerment climate serves as the mechanism translating the influence from organizational level to individual level and its effect on ERP assimilation at the individual level is mediated through psychological empowerment. Furthermore, empowerment climate is also argued to dampen the direct effect of top management championship on ERP assimilation in value-chain activities. The theoretical and practical implications are discussed.