Introduction: Nomophobia, as the irrational fear or anxiety of being away from a mobile phone, is highly prevalent among students and can negatively impact mental health and academic performance. This study examined the relationship between emotion regulation strategies (cognitive reappraisal and expressive suppression) and nomophobia among university students.

Research Methodology: This descriptive–correlational study was conducted with 300 students (150 male, 150 female) from universities in Tehran. The instruments included the Nomophobia Questionnaire (20 items; reliability α = 0.89) and the Emotion Regulation Questionnaire (10 items; subscale reliabilities α = 0.87 and 0.83). Data were collected after obtaining informed consent and analyzed using Pearson’s correlation, independent t-test, and one-way ANOVA in SPSS-26 (significance level set at 0.05). To control for common method bias, Harman’s single-factor test was applied.

Findings: Findings indicated that nomophobia was high among students and had a significant positive association with expressive suppression but no relationship with cognitive reappraisal. Female students scored higher on both nomophobia and cognitive reappraisal, whereas male students reported greater use of expressive suppression. Moreover, undergraduates obtained higher scores than graduate students on nomophobia and cognitive reappraisal. Among the nomophobia dimensions, “inability to access information” and “anxiety from being away from the mobile phone” showed the strongest associations with expressive suppression.

Conclusion: Nomophobia is prevalent among students and strongly linked to expressive suppression. Gender and academic level differences exist, with women and undergraduates showing higher scores. Interventions should focus on teaching adaptive strategies like cognitive reappraisal to reduce nomophobia.