Fear of Missing Out (FOMO) has emerged as a salient psychological concern among university students in relation to intensive social media use. While previous studies have consistently reported a positive association between social media use and FOMO, limited attention has been given to Islamic self-control as an underlying psychological mechanism within Muslim populations. This study examined the mediating role of Islamic self-control in the relationship between social media use intensity and FOMO among Muslim university students. A quantitative cross-sectional design was employed involving 208 Muslim university students aged 18–25 years in Indonesia. Data were collected through an online survey using Indonesian-adapted measures of social media use intensity, Islamic self-control, and FOMO. Mediation analysis was conducted using Hayes’ PROCESS Model 4 with 5,000 bootstrap resamples. The findings showed that higher social media use intensity was associated with higher FOMO and lower Islamic self-control, while Islamic self-control was negatively associated with FOMO. Mediation analysis confirmed a significant partial indirect effect through Islamic self-control. As a novel contribution, this study extends existing FOMO literature by examining Islamic self-control as a mediating mechanism within an Islamic psychological framework. The findings contribute to the growing body of Islamic psychology research and suggest that strengthening Islamic self-control may represent a relevant avenue for reducing vulnerability to FOMO among Muslim university students in digital environments.