Objectives: To evaluate the association between dental service utilization and mental health in an adult population in the context of the socioeconomic status of the participants. Subjects and Methods: Multi-stage cluster random sampling was performed in Tehran, Iran, in 2011. Data were collected on dental service utilization, barriers of dental visit, self-perceived oral health, mental health, age, gender, education, and wealth status. The complex sample analysis method in SPSS and the survey data analysis menu in STATA were employed for statistical evaluation. Results: Of 20,320 participants, 25–36% suffered from disorders in at least one of the domains of somatization, anxiety, social dysfunction, and depression. Only 56% of the participants visited a dentist at least once during the last year. The main barriers to a dental visit were “no perceived need” and “high costs.” Females, the richest participants, subjects aged 25–64-year-old, and those with poor self-perceived oral health, mental health disorders, and higher education had more visits. The participants who perceived the need but did not visit a dentist due to some reasons mostly comprised females, those aged 25–44-year-old, those with a poor perceived oral health, disordered people in all domains of mental health, and poorer participants. Conclusion: Dental service utilization was influenced by socioeconomic factors and the mental health status of the adult population after controlling for multiple confounders. Reducing financial hardship and providing health education on the importance of preventive visits may decrease barriers to regular visits in countries with developing oral health systems.