Revana Dinar Ayu Nastiti. The Effect of Green Intellectual Capital, Green Accounting, and Material Flow Cost Accounting on the Environmental Performance of Mining Companies in the period 2019-2023. Under the guidance of Mrs. Yana Ulfah. This study aims to The Effect of Green Intellectual Capital, Green Accounting, and Material Flow Cost Accounting on the Environmental Performance of Mining Companies Listed for the 2019-2023 Period and have participated in PROPER for the 2019-2023 period. This study is quantitative, using secondary data in the form of annual reports and sustainability reports from 12 companies that published annual reports and sustainability reports during 2019- 2023 consecutively and have participated in PROPER for the 2019-2023 period. The sample of this study was selected using the purposive sampling method. Data analysis was carried out using the SPSS version 26 analysis tool and using multiple linear regression techniques. The results showed that the application of green intellectual capital has a significant positive effect on environmental performance, then the application of green accounting has a significant positive effect on environmental performance, and the application of material flow cost accounting has a significant positive effect on environmental performance.