Greenwashing (GW) is a complex, dynamic, interdisciplinary, multidimensional, and multifaceted phenomenon. There are more theoretical than empirical studies on GW because of several difficulties in collecting accurate data and obtaining objective GW measures. After disentangling the multifaceted GW phenomenon by describing its main dimensions, this study provides a systematic methodological literature review on empirical research papers published from 1990 to 2022 in journals of Business, Management, and Accounting to understand how empirical researchers are operationalizing GW and how our methodological choices (...) affect our understanding of this phenomenon. Our results show that the actual GW operationalization is challenging and that scholars are highly uncertain about how such operationalization should be designed and implemented to provide an effective GW measurement instrument. Further, a growing number of studies investigate hypothetical GW cases adopting perception-based measures, while limited research explores real GW cases. (shrink)