This study analyzes how market competition influences the performance of firms in Indonesia. In this study, performance is measured with the help of ROA, ROE, and ROS, while the Boone Indicator is used as the measure of competition intensity. The panel data analysis is conducted through the application of a two-step System GMM estimator in order to handle problems of endogeneity and unobserved heterogeneity. The sample contributing to the paper consists of 421 public companies during an 11-year period, from 2013 to 2023. It follows that the result obtained from the preceding indicates that the relationship between competition and ROA is nonlinear and statistically significant enough to confirm the inverted U- shape hypothesis. However, in the case of ROE and ROS, the findings indicate slightly inverted U-shaped relationships, with less pronounced evidence. More precisely, diagnostic tests, for instance, Arellano-Bond test for autocorrelation and the Sargan-Hansen test for overidentification-confirm the reliability of the model of ROA, ROE and ROS.