This study explores the impact of service quality, as evaluated using the CARTER model, on customer satisfaction at Bank Syariah Indonesia. Among the six initial hypotheses, only two were confirmed, yielding significant insights. Notably, the research revealed that neither sharia compliance nor tangible aspects significantly influenced customer satisfaction. Assurance and empathy also displayed no substantial impact. Conversely, two pivotal factors emerged as major drivers of customer satisfaction: reliability and responsiveness. This intriguing finding may be linked to a recent hacker attack on Bank Syariah Indonesia, which occurred a month before the study, although further research is required to confirm this hypothesis. Despite the rigor of the research procedures, some limitations emerged, including the use of online questionnaires via Google Forms, which hindered detailed explanations to respondents and potentially affected their understanding. Additionally, the study focused exclusively on the service quality components outlined by the CARTER model, neglecting other important variables like trust, awareness, and loyalty. In light of these findings, the study offers vital recommendations. Bank Syariah Indonesia is encouraged to focus more on the various components of the CARTER service quality model to potentially foster higher customer trust and loyalty. Furthermore, the bank should consider introducing flagship programs and comprehensive approaches to enhance customer satisfaction. Future researchers are encouraged to explore additional factors influencing customer satisfaction, such as product quality and brand image, and to expand the sample to include a more diverse range of respondents. In summary, this study summarizes its findings, limitations, and recommendations, providing valuable insights for Bank Syariah Indonesia and future researchers seeking to enhance their understanding of service quality and customer satisfaction in this context.