["Business Strategy and the Environment, Volume 35, Issue 3, Page 3177-3197, March 2026. ", "\nABSTRACT\nThe shift from traditional operations model to sustainable production and consumption paradigms such as circular economy (CE) has made the domain of CE a fertile avenue for theory development and theory utilization. Theories are essential requirement for the advancement and maturation of any scholarly field of study. However, studies on theories and theoretical approaches in CE research are still patchy. This affects our understanding of the inventory of theories and the theoretical approaches employed in the CE domain. Therefore, this current study used the systematic review approach (with the aid of content analysis) to analyze 655 articles distilled from the Scopus and Google scholar databases. The study identified 97 specific theories in the sample. These theories were then classified under various categories: socioecological, competitive, inventory, economic, etc. The resource‐based view, theory of planned behavior, stakeholder, institutional, game, and natural resource‐based view were some of the major theories identified. The study also illustrates the procedure for selecting and testing theories in CE research. This study offers scholars, reviewers and editors detailed insights on the usage of theories in CE research. This study will provide scholars with the needed impetus to develop theories in CE and may limit the borrowing of theories from other domains to the CE studies. To the best of the researcher's ability, this is the pioneering attempt to comprehensively offer a structural perspective into the theories and the theoretical techniques used in CE studies.\n"]