Sustainability reports enable businesses to inform the public about their progress towards their goals, including environmental, social and management measures, and the risks they may face now or in the future. Because businesses play an active role in the sustainable development process, investors are more interested in the activities of businesses and the impact of these activities on the environment. In this study, the sustainability reports of the companies included in the Borsa Istanbul (BIST) sustainability 25 index were evaluated. Using a sample of 16 companies included in the Borsa Istanbul sustainability 25 index and publishing sustainability reports in 2021, text analysis was conducted to identify trends in sustainability reports. The analysis process was carried out using the Python programming language. According to the results of the analysis obtained, it was determined that 81% of the sustainability report statements showed positive sensitivity and 19% had negative sensitivity. In addition, in the study, LDA topic modeling and distance mapping were applied to 16 sustainability reports, and it was observed that reports 2, 15, 6, 13 and 8 overlapped with each other as a result of the application. It was assumed that there was no definitive word list for each report, as no heavy overlap was found between the other reports. Therefore, we can state that the PyLDAvis package included in the Python software is an effective tool for identifying overlaps and the most important themes among sustainability reports.