The social capital embedded within the social network relationships among users may facilitate their continued usage of mobile SNS. However, how to develop social capital remains a question. In this article, the authors incorporated three factors of system quality, information quality, and service quality from the information systems (IS) success model to examine their effects on social capital in mobile SNS. The results indicate that these three factors have significant effects on social capital, which includes structural capital, relational capital, and cognitive capital. The results imply that service providers need to improve users' technological perceptions in order to develop social capital and facilitate their continuance of mobile SNS.