ABSTRACT : The purpose of this study was to determine the effect of company size, leverage, and environmental performance on the area of sustainability reporting. This research was conducted at companies listed in the LQ45 index. The number of samples taken were 8 companies, using all the company’s annual reports and sustainability reports for the 2015-2018 period. The analysis technique used is multiple linear regression analysis. Based on the results of the analysis it was found that company size and environmental performance had a positive and significant effect on the area of sustainability reporting. This shows that the larger the company, the company will report more items on its sustainability reporting and the better the company’s environmental performance, the number of items disclosed in the sustainability report will be more. While the leverage variable does not directly influence the sustainability reporting. This research confirms stakeholder theory and legitimacy. KEYWORDS : Company Size; Leverage; Environmental Performance; Sustainability Reporting