The rise of super apps has attracted scholarly attention across different disciplines. Integrating the theories of service extension and status quo bias into a three-component model under the S–O-R framework, this study attempts to build a model accounting for mobile payment adoption among super apps users. Taking LINE and LINE Pay as our research context, our data analysis consisting of 358 LINE users revealed that from a core app perspective, trust toward the core app, inertia and habit of using the core app are all positively related to attitudes toward the service extension. For the service extension itself, the relative advantage compared with other apps is found to be positively related to attitudes. Finally, the synergy and fit of the core app and the service extension seem to play the most prominent role in determining attitudes, while privacy concerns are negatively related to attitudes.
