Abstract. This study aims to analyze the effect of environmental performance announcements on shareholder value and how environmental disclosures mediate this relationship. The companies studied included 81 companies listed on the Indonesia Stock Exchange (IDX) in 2017–2019. Researchers determine the sample using purposive sampling, with the criteria 1) manufacturing companies that issue financial reports. 2) manufacturing companies that follow PROPER. 3) manufacturing companies that publish environmental disclosures in Sustainability Reporting. The results showed that the first hypothesis, namely the announcement of environmental performance has a positive effect on environmental disclosure, is accepted. Furthermore, the second hypothesis is that environmental performance announcements have no effect on shareholder value, and the third hypothesis is that environmental disclosure has a positive effect on shareholder value.