In today’s business landscape, environmental, social, and governance (ESG) considerations have become increasingly vital. ESG policies not only assist companies in addressing global challenges like climate change, resource scarcity, and social inequality but also empower those with robust ESG initiatives to minimize operational risks, streamline business costs, and uphold compliance with regulatory standards. This positions them as safer and more appealing investment choices. ESG data plays a pivotal role for investors, companies, and other stakeholders keen on evaluating investments or businesses’ sustainability and ethical impact. Numerous sources offer ESG data, each with varying degrees of reliability. This chapter explores ESG metrics and their dependability, ESG performance indicators, and the incorporation of ESG data in investment analysis and showcases examples of prominent ESG sources, ratings, and indices.