Customer are greatest asset in determining the development of the company, because the customer is not only as a buyer but also as a partner in the company. Therefore, the company must perform a variety of ways to attract new customers an retain existing customers so that the company can continue to grow continuation. The purpose of this final report is to know the influence of product quality and after sales service on customer loyalty at PT Sun Star Motor Branch MT. Haryono Semarang. Methods of data collection in this study is quistionnaires filled out by respondents are customer of PT Sun Star Motor Branch MT. Haryono Semarang that have been bought product and receive after sales service at least twice. Taking sample of 30 respondents in this study using a purposive sampling method. The analysis data use the method of multiple linear regression coefficient analysis. Regression analysis is used to determine the influence of quality product and after sales service to customer loyalty. Data are processed using SPSS 18.00. The result of this studt is that the calculation of regression coefficients obtained Y = 0.667 + 0.432X1 + 0.367X2. it means that result of regression give positive influence on customer loyalty, and the influence of after sales service on customer loyalty is greater than the quality product quality. The coefficient of determination is 0.312. It means that the customer loyalty of 31.2% is influence by product quality and after sales service. While the rest of 68.8% is influence by other factors.