Customer satisfaction (CS) is critical to success in banking. However, there is little agreement on which antecedents can be employed to achieve it. Moreover, in the context of Islamic banking, religiosity plays a major role in affecting customers' choice of bank and banking satisfaction. In response, this thesis developed an Islamic religiosity scale measurement and an integrated model of customer satisfaction for Islamic credit-card users. In particular, this thesis sought to investigate the role of religiosity and antecedents of Islamic credit-card users' satisfaction. Furthermore, it presented and discussed empirical findings from mixed methods approach employing semi-structured interviews of seven respondents and an online survey of 560 credit-card users in Malaysia. The study used confirmatory and structural equation modelling to examine the survey data. The findings of this thesis largely support the hypothesised relationships proposed in the theoretical model. Specifically, the results revealed that the functional service quality (FSQ), technical service quality (TSQ) and the religious and ethical service quality (RESQ) are crucial and differ in affecting customer satisfaction. The results also provide strong evidence that religiosity moderates between the antecedents and customer satisfaction. Most importantly, Shari'ah compliance and ethical dimensions (constructs in RESQ) are necessary determinants of Islamic credit-card users' satisfaction. This thesis contributes to the existing theoretical and practical knowledge by providing, for the first time, an Islamic religiosity scale measurement. Secondly, evidence is presented that religiosity plays a significant contribution towards the customer satisfaction model. Thirdly, the integration of FSQ, TSQ and RESQ creates a comprehensive Islamic customer satisfaction model. Fourthly, since the integrated model involves religious factors (i.e. Shari'ah compliance), religiosity contributes to the variation of customer satisfaction. The inclusion of Shari'ah compliance, ethical dimensions, technology and communication as first order constructs and FSQ, TSQ and RESQ as second order constructs contribute to the body of customer satisfaction and Islamic banking literature. The findings imply the need for the banks to lever on the key antecedents of customer satisfaction, which include Shari'ah compliance and ethical dimensions.