The purpose of this study was to determine the determinants of good corporate governance and ownership on firm value in manufacturing companies listed on the IDX for the 2019-2021 period. This study uses a quantitative method research design with a correlational approach to test the effect of independent variables and mediating variables on the dependent variable. The sample of this study were 31 manufacturing companies that have been listed on the IDX for the 2019-2021 period or for 3 years of observation. The data used in this study are secondary data obtained from the company's financial statements and the Indonesia Stock Exchange. The results of testing 11 hypotheses show that good corporate governance has a significant effect on firm value, firm value has a significant effect on asset growth and ownership has a significant effect on firm value. In addition, indirect effect testing also shows that there is no mediating influence between variables.