Purpose -This study aims to identify factors that influence corporate environmental disclosure (CED) quality. Design/methodology/approach -Using content analysis, an index and scoring scheme were applied to annual reports, stand-alone reports and corporate homepages of a sample of 116 oil and gas companies in 19 developing countries (DCs).Findings -The results of this study reveal that out of 12 hypothesized variables, only 5 variables (company size, foreign ownership, profitability, leverage and membership of industry's associations) are positively related to the CED quality.Practical implications -The study has implications in enhancing the understanding of CED practices by oil and gas companies in DCs and the factors that influence the quality of such disclosure. Thus, the results of the study serve as input toward the development of improved regulations concerning CED for the oil and gas industry and provide guidelines to the regulators to make relevant decisions on social and environmental information items to be incorporated in the regulatory standards.Originality/value -The current study attempts to fill the gaps in the literature by examining CED quality (rather than its quantity), concentrating on environmental disclosure made on the three main mediums of reporting. The study also extends previous research of CED by investigating some factors that have the potential to influence the content-quality of environmental disclosure, such as type of company (independent or constrain company) and industry's association membership which have never been examined in the related literature.