ABSTRACTDrawing on the Planned Risk Information Seeking Model (PRISM), research on social norms in communication, and literature on emotion regulation, the current study examines the relationships among poly social media COVID-19 health information searches, informational norms, and health protective behaviors (further interpersonal information seeking and protective measures) during the pandemic. In addition, we explore the moderating role of negative emotions (i.e. anxiety and fear). A cross-sectional survey ( N = 510) during an early phase of COVID-19 suggests that the association between social media use and influenced behaviors functions to the extent that individuals perceive the behaviors are expected norms. Even such a mechanism is valid only in some boundary conditions such as emotional states.