This study aims to examine The Effect of Capital Adequacy Ratio, Return On Assets, Financing to Deposit Ratio, and Net Profit on Financial Sustainability of Islamic Banks in QISMUT Countries. The independent variables in this study are Capital Adequacy Ratio (CAR), Return On Assets (ROA), Financing to Deposit Ratio (FDR), and Net Profit. While the dependent variable is the Financial Sustainability Ratio (FSR). The research object is the Sharia bank operating in QISMUT countries. Sampling using purposive sampling technique to 12 Islamic banks.The data analysis method uses panel data regression analysis with Random Effect estimation model, classical assumption test, and hypothesis testing with the help of SPSS 26 and Eviews 11.The t test results show that CAR has a significant negative effect, ROA has a significant positive effect, FDR has a positive and insignificant effect, Net Profit has a negative and insignificant effect. Meanwhile, the results of the F test show that together all independent variables have a significant effect on the dependent variable with an adjusted R2 of 0.463656.