Purpose: Mobile instant messaging (MIM) applications have grown profusely worldwide in recent years in tandem with increased smartphone usage. The purpose of this paper is to examine the relationships among perceived benefits, personality traits, MIM satisfaction, and social capital responses. Design/methodology/approach: This paper uses partial least squares-SEM to investigate proposed hypotheses based on a sample of 1,519 WhatsApp users. Findings: The results indicate that perceived benefits of MIM and personality traits have a positive influence on MIM satisfaction; and MIM satisfaction in turn has a positive effect on users’ social capital responses. MIM satisfaction partially mediates the relationships between perceived benefits, traits, and social capital. Additionally, the results indicate positive significant effect of Gen X and Y on social capital among other control variables. Research limitations/implications: This study contributes to the growing body of knowledge on MIM. The results also provide important implications for MIM application developers and instigate future research in the MIM platform. Originality/value: This study is the first attempt in integrating perceived benefits, personality traits, and social capital in MIM literature. © 2018, Emerald Publishing Limited.