The purpose of this study was to test and analyze the effect of Good Corporate Governance (GCG) and others: managerial ownership, number of Board of Commissioners and Audit Committee, and Financial Performance, which included ROA and ROE on company sustainability in banking sub-sector companies listed on the Indonesia Stock Exchange. In addition, this study also aims to determine whether the firm size can be used as a moderation variable to strengthen or weaken the relationship between good corporate governance (GCG) and the financial performance of the company's sustainability. This research is a type of quantitative research with a descriptive approach. Purposive sampling techniques were used from 47 banking companies in the IDX, and 19 banks were included in the research sample within 6 years of the period. The data used are secondary data and data collection methods, accessed by accessing the IDX's 2017-2022 annual report. The results of this study show that good corporate governance (GCG) has no significant effect on sustainability. The audit committee has no significant effect on sustainability reports. Managerial ownership has a significant effect on sustainability reports, independent commissioners have no significant effect on sustainability reports, the Board of directors has no significant effect on sustainability reports, and financial performance has a significant effect on sustainability reports, where ROA and ROE have a significant effect on sustainability reports. Firm size can moderate the influence of GCG and financial performance with sustainability reports. Keywords: good corporate governance, audit committee, board of commissioners, managerial ownership, financial performance, ROA, ROE, sustainability report, and firm size