Purpose: The purpose of this paper is to analyze more than three decades of theory testing published in leading operations management (OM) journals. Design/methodology/approach. This piece examines the amount of theory testing, the extent to which theories are tested multiple times, and the disciplinary origins of the theories that are tested. Findings: The analysis revealed that empirical OM researchers have increasingly responded to demands for more theory-driven knowledge over time. OM researchers are developing and using a wide array of domestic theories to understand empirical data. The examination also revealed a substantial focus on theory borrowed from other scientific fields. Originality/value: The findings here suggest that OM is clearly a maturing discipline. As the discipline matures, it is important to consider to what extent borrowed theories and frameworks can offer value to OM. A preliminary vetting model is advanced in order to critically assess foreign theory. It is hoped that future screening promotes only the most useful non-domestic theory, thereby ensuring sufficient journal space for domestic theory and resulting in effective solutions to the pressing, practical problems of the OM field.