This study examines the relationship between Good Corporate Governance (GCG) components and tax aggressiveness in real estate sector companies in Indonesia from 2014 to 2023. The research consists of two main parts: first, it investigates the role of institutional ownership in tax aggressiveness, and second, it analyzes the influence of other structural variables such as the number of independent commissioners, commissioners’ educational background, audit quality, company size, debt ratio, Return on Assets (ROA), asset growth, and company age. The results show that institutional ownership has a significant positive impact on reducing tax aggressiveness. Additionally, factors such as ROA and audit quality also influence the level of tax aggressiveness. However, other variables like company size and debt ratio do not show a significant effect on tax aggressiveness. The study suggests that companies, regulators, and investors should pay more attention to institutional ownership composition as an important indicator for transparent and accountable tax policies. , commissioners’ educational background, audit quality, company size, debt ratio, Return on Assets (ROA), asset growth, and company age. The results show that institutional ownership has a significant positive impact on reducing tax aggressiveness. Additionally, factors such as ROA and audit quality also influence the level of tax aggressiveness. However, other variables like company size and debt ratio do not show a significant effect on tax aggressiveness. The study suggests that companies, regulators, and investors should pay more attention to institutional ownership composition as an important indicator for transparent and accountable tax policies.