This study explored the relationship between fear of missing out (FOMO) and student engagement, examined the mediating role of social media engagement, and determined whether action control strategies moderated this relationship. We recruited 400 Taiwanese college students, collecting data on FOMO, student engagement, social media engagement, and action control strategies use. The results revealed that FOMO was negatively related to student engagement, mediated by social media engagement. Students with higher FOMO levels paid more attention to others' information on social media, which was negatively related to student engagement. Additionally, action control strategies moderated the relationship between FOMO and student engagement. Among students using fewer action control strategies, the relationship between FOMO and student engagement was negative. However, among students using more action control strategies, FOMO was not related to student engagement. Hence, integrating action control strategies into learning may potentially protect against the tendency of FOMO inducing low student engagement.