The purpose of this research is to propose a six-level ERP integration model and to empirically investigate if each of the six levels exists. The six levels are system-specification, system–user, islands-of-technology, organizational, socio-organizational, and global integration. Empirical data were collected by using a large-scale survey of ERP professionals. We conducted various validity and reliability tests to confirm the proposed theoretical framework. Using partial least squares (PLSs) analysis, the results of the investigation confirmed the existence of the six levels of ERP integration. The results of the investigation have implications for research and practice.