In recent years, there has been a notable increase in the use of e-banking. In recent times, online technologies have revolutionized the process of relationship building between firms and their customers. A reality that has led financial institutions to be increasingly closer to their customers and to make their services available on the most diverse distribution channels. Given Portugal's wide range of banking services, these new marketing trends may impact consumer choice and preference. This paper aims to study the determinants of e-loyalty involved in the banking sector's relationship with its customers from the perspective of relational marketing online. In this way, internet banking and interactivity are essential variables in achieving quality of service in e-banking. In turn, quality of service proved to be a fundamental antecedent of customer satisfaction, and these two variables determine customer loyalty to the use of e-banking. Therefore, e-service quality and e-satisfaction mediate between the independent variables, internet banking and interactivity, and the final variable, customer e-loyalty.