Recently, the number of smartphone users has skyrocketed because of a plenty of useful services that smartphone applications provide. In the Information Systems (IS) literature, however, there has been little understanding about the effects of the service quality of smatphone applications on user satisfaction and loyalty. Thereby, this study examined 1) the effects of the service quality of smartphone applications on users beliefs, perceived usefulness and easiness and 2) the effects of the user beliefs as mediating variables on users' attitude, satisfaction, and loyalty. A survey was conducted and SEM was employed to analyze the data. The results showed that the service quality of smartphone applications affect users' attitude, satisfaction, and loyalty through the mediating variables.