["Journal of Economic Surveys, EarlyView. ", "\nABSTRACT\nThe major global challenges of climate change, environmental degradation, and resource scarcity have gained centrality in policymaking and academia, with a growing body of research exploring the interlinkages among economic growth, trade, environmental outcomes, and policy interventions. These analyses and their results draw fundamentally on the definitions used to consider a firm, product, or process “green,” and on the related operationalization. Despite a proliferation of empirical approaches, however, the literature lacks a comprehensive overview of firm‐level sustainability indicators. This article addresses this gap by systematically reviewing existing definitions and the most frequently employed indicators Our analysis shows that, according to prevailing definitions of greenness, a firm can be considered green either because it is purpose‐sustainable, meaning that it primarily serves an environmental purpose, or because it is process‐sustainable, meaning that its activities reduce or prevent negative environmental impacts even if environmental goals are not its primary purpose. We further classify the existing firm‐level sustainability indicators into three groups: (1) product‐level indicators; (2) resource and pollution management indicators; and (3) investment, innovation, and commitment indicators. Our findings aim to support researchers in selecting indicators that align with specific research objectives and dimensions of sustainability under investigation.\n"]