Abstract
While Circular Economy (CE) adoption is growing worldwide, its systematic assessment remains a challenge. This paper aims to shed light on the strengths and weaknesses of firm-level CE assessment tools and to theorize on the CE assessment issue. Four tools were selected and compared based on a comparison analysis as well as on multiple case study analyses on Italian SMEs. The main results indicate that the tools can be improved in terms of transferability, confirmability, fit and generality. Accordingly, this study provides suggestions to improve the development of tools, that are of relevance for both theory and management practice.