The growing number of internet banking (i-banking) users in Bangladesh requires examining their behavioral intention (BI) to adopt i-banking services. This study aims to investigate the factors that influence the customers’ intention in i-banking adoption encompassing the moderating effect of demographic characteristics. This study uses an expansive approach of the Unified Theory of Acceptance and Use of Technology (UTAUT) model with customer satisfaction. The structural equation modeling (SEM) has been used to analyze the data collected from the internet banking users of Bangladesh. Findings of the study conclude that the higher the level of performance expectancy (PE), effort expectancy (EE) and social influence (SI), the greater the level of customers’ inclination to adopt i-banking. Whereas, facilitating condition negatively affects their BI in i-banking adoption. Moreover, this study finds a positive and significant impact of system, service and information quality and security, privacy and trust (SPT) on customers’ satisfaction, which, in turn, substantially influence their intention toward i-banking adoption. While investigating the moderating effect of demographic characteristics, this study finds that all categories of customers, regardless of their age, gender, experience and education, are influenced by the customers’ satisfaction of services qualities and trust perception in i-banking adoption. Therefore, it is suggested to the policymakers that they should take such initiatives in designing the i-banking system that satisfy the customers’ expectations.