This paper offers the first systematic evidence on environmental, social and governance (ESG) disclosures provided by a large global sample of private equity (PE) firms. Using historical websites from 2000 to 2022, we develop and validate a novel dictionary-based measure of voluntary PE firm ESG disclosures. Descriptive statistics suggest an increasing trend in these disclosures over time. Multivariate analyses show that the demand for sustainable investments from PE fund investors and mandatory ESG disclosure regulations aimed at publicly listed firms in countries where PE portfolio companies operate are significant determinants of PE firms’ ESG disclosures. Leveraging data on PE firms’ portfolio companies, we document evidence implying active ESG outcome improvements when PE firms provide more ESG disclosures. Overall, these findings indicate that the actions of PE firms align with their ESG disclosures.