Background <p>Although there has been a recent shift to investigating interpersonal emotion regulation (IER), there are still key aspects of IER to understand. Examining how emerging adults, including those with social anxiety, utilize and think about IER can provide insights into how this type of emotion regulation can impact well-being. It is valuable to have investigated IER during the pandemic since in-person interpersonal interactions may have been disrupted due to physical distancing. Thus, the current study examined the relations between social anxiousness, IER, and well-being during this time.</p> Method <p>Emerging adults (<i>n</i> = 674) completed measures related to social anxiousness (social interaction, performance, and scrutiny anxiety as well as avoidance), IER (tendency and efficacy for positive and negative emotions), and well-being (subjective happiness, life satisfaction, and flourishing).</p> Results <p>Through a structural equation mediation model, it was demonstrated that social anxiousness is inversely linked to well-being and IER, and IER is positively linked to well-being in the context of the pandemic. Importantly, IER acted as a partial mediator on the link between social anxiousness and well-being.</p> Conclusions <p>These results underscore the important role of IER, as well as social anxiety, on emerging adults’ well-being. Additionally, IER could act as a mechanism partially explaining the inverse relation between social anxiety and well-being levels in emerging adults. Further, our findings provide a crucial starting point to inform future research and clinical interventions based on IER.</p>