This study aims to determine how internal marketing influences the quality of customer service at Banks Syariah of Palembang City. This study uses quantitative methodology to conduct a descriptive survey. Cross-sectional survey is performed for 135 respondents, 45 staff members, and 90 Banks Syariah customers from nine Banks Syariah in Palembang City using a standardized questionnaire. The data were evaluated using linear regression and structural equation modeling approaches (SEM). The study's findings indicate that the implementation of internal marketing significantly affects the service quality offered to Banks Syariah clients. In addition, the developed model satisfied the fit criteria of several techniques, indicating that employing internal marketing to train personnel can improve the quality of customer service. This is innovative that it explores and proves a model and influence of internal marketing on the quality of customer service for Banks Syariah in Palembang City. Limited number of respondents in this survey, who are all from Palembang, cause findings cannot be generalized to the entire Indonesia. Implications for practice: This study is limited to respondents from Palembang, so it cannot be extrapolated to the rest of Indonesia. By employing internal marketing tactics, this study will increase the social acceptability of Bank Syariah.