Information and communications technologies promote change in the service sector, and the banking sector is not an exception. Finding what factors impact consumer satisfaction with service and lead to loyalty is invariably important for business. However, it is important to begin with evaluating the aspects that are specific to the market and service. The purpose of this study was to investigate the factors affecting customer loyalty in Mobile Banking. Following the model designed by the researchers, consideration was given to mediator variables of satisfaction, trust, and customer service to examine how factors such as perceived risk, relative advantages, and usability affect customer loyalty. In this study, customers of an Iranian bank (Shahr Bank) based in the city of Tehran constituted the statistical population. The descriptive survey method was used on a sample that was selected through a cluster-convenience method and included 411 Shahr Bank's customers resident in the east, west, north, south, and centre of the city of Tehran. Structural Equation Modelling (SEM) test and the LISREL 8.8 software were used to analyse the data and to determine what role each factor plays on loyalty. The results showed that such factors as relative advantages, satisfaction, and trust have the most significant impact on customer loyalty. However, the effect of usability on customer service was not confirmed. Furthermore, it was identified that perceived risk has a negative impact on loyalty.