Organizational Citizenship Behavior (OCB) is a form of voluntary behavior demonstrated by employees in providing positive contributions to organizational effectiveness. This study aims to analyze the effect of Quality of Work Life (QWL), transformational leadership, and organizational culture on Organizational Citizenship Behavior (OCB) at PT BPR Syariah Mitra Mentari Sejahtera. This research employs a quantitative approach using a survey method through the distribution of questionnaires. The research population consists of all employees of PT BPR Syariah Mitra Mentari Sejahtera, with a total of 55 respondents determined using a saturated sampling technique. The data analysis technique was conducted using multiple linear regression with the assistance of SPSS software. The results of the study indicate that: (1) Quality of Work Life (QWL) has an effect on Organizational Citizenship Behavior (OCB), (2) transformational leadership has an effect on Organizational Citizenship Behavior (OCB), (3) organizational culture has an effect on Organizational Citizenship Behavior (OCB), and (4) Quality of Work Life (QWL), transformational leadership, and organizational culture simultaneously affect employees’ Organizational Citizenship Behavior (OCB). Based on these findings, it can be concluded that improving the quality of work life, implementing transformational leadership, and strengthening organizational culture play important roles in encouraging higher levels of Organizational Citizenship Behavior (OCB) among employees of PT BPR Syariah Mitra Mentari Sejahtera.