Objective: The present study was conducted with the aim of investigating the prevalence of mental disorders among elementary school students (second term) in single-child families with both working parents in Tehran.

Research method: In this research, a descriptive-survey method and an epidemiology type was used. The statistical population of this research was made up of all elementary school students (second period) in single-child families with both working parents in Tehran. The sample of this research included 384 students with both working parents in Tehran, the sampling method in this research is available in the form of cluster sampling. In this research, the DSM-5 questionnaire of Motamedin et al. (1400) was used to collect information. Finally, after collecting the data, the data was subjected to SPSS version 27.

Findings: The results showed that the prevalence of disorders in students was 10% conduct disorder, 38% hyperactivity, 31% inattention, 25% academic learning, 22% separation anxiety, 25% stubbornness and disobedience, and 14% social communication. It was a percentage.

Conclusion: Despite the existing educational and educational efforts and programs, there are significant behavioral problems among primary school students, which requires families and schools to pay more attention to take necessary interventions.