This study investigated the determinants of mobile payment adoption in Taiwan. Based on Social Cognitive Theory (SCT) and the fundamental principle of the Technology Acceptance Model (TAM), this study proposed a moderated mediation model to examine the mediating effect of perceived usefulness on the relationship between perceived ease of use and behavioral intention. Regarding facilitating conditions and perceived value as environmental and personal factors respectively, the moderating effects of facilitating conditions and perceived value on the aforementioned mediation relationship were explored. A total of 377 valid responses of Taiwan’s mobile payment users were collected in an online survey. The empirical findings validated the mediating role of perceived usefulness. For moderating effects, both facilitating conditions and perceived value had a positive relationship with the indirect effect of perceived ease of use and behavioral intention through perceived usefulness. Practical implications and future research are then discussed.