This study investigates the effect of retail service quality on customer loyalty in modern minimarkets located in Medan City, with customer satisfaction playing a mediating role. Data were gathered through questionnaires from 115 respondents, specifically customers of Alfamidi in Medan. Using a quantitative, associative approach, the research analyzes relationships among variables, with data processed through Partial Least Square (PLS) techniques, a method well-suited for analyzing predictive models in social science research. The results indicate that the quality of retail service has a substantial impact on consumer satisfaction and loyalty. Furthermore, the relationship between customer loyalty and retail service quality is mediated by customer satisfaction. These findings indicate that in order to further enhance consumer loyalty, retail management should prioritize the enhancement of the overall purchasing experience and the optimization of service quality.