The rapid advancement of financial technology (FinTech) has significantly transformed payment systems worldwide, accelerating the transition from cash-based transactions to digital payment methods. In Cambodia, the introduction of mobile QR code payment systems, particularly through KHQR and Bakong platforms, has promoted widespread adoption of cashless payments. However, while existing studies have primarily focused on initial adoption, limited research has examined the factors influencing users’ continuance intention to use mobile QR code payment systems. Therefore, this study aims to investigate the key determinants of continuance intention in the Cambodian context. This study is primarily based on the Unified Theory of Acceptance and Use of Technology (UTAUT) framework. Performance expectancy, effort expectancy, social influence, and facilitating conditions are examined as key factors influencing user satisfaction, which subsequently affects continuance intention. In addition, perceived security is incorporated as a moderating variable to examine its role in strengthening the relationship between these factors and user satisfaction. Data were collected from 230 users of mobile QR code payment services in Cambodia through a structured survey questionnaire. The data were analyzed using statistical techniques, including reliability analysis, correlation analysis, and regression analysis. The results reveal that performance expectancy, effort expectancy, social influence, and facilitating conditions have significant positive effects on user satisfaction. Furthermore, user satisfaction has a strong positive influence on continuance intention. The findings also highlight the important role of perceived security in enhancing users’ confidence and supporting continued usage behavior.