With advances in information technology (IT), information systems integration (ISI) and its roles in enhancing supply chain integration (SCI)have become important to executives and researchers. ISI represents the degree of cooperation in information system practices between business functions within a firm (Internal Integration) and between a firm and its trading partners (External Integration). The concept of ISI was captured using two main sub-constructs (e.g., internal ISI and external ISI) and each can be conceptualized into three sub-levels (1) Strategic Integration, (2) Operational Integration, and (3) Infrastructural Integration. Studying the effects of ISI in three levels can help researchers and managers understand how IS practices at different levels contribute to overall supply chain effectiveness. The implications of such an understanding may bring significant benefits to both operations researchers and practitioners.