Objectives: Studies have shown that mental health problems at an early age can lead to greater impairment in adult life. Epidemiological evidence on the prevalence and incidence of mental health disorders is fundamental for planning mental health services. However, these data are lacking in Saudi Arabia. The current study examined the prevalence of mental health problems in Saudi children and adolescents living in a selected community in Riyadh City. Methods: This two-stage epidemiological study used the Strengths and Difficulties Questionnaire (SDQ) to screen all eligible participants for the presence of a possible psychiatric disorder. The screening was followed by the use of a structured psychiatric interview (MINI-Kid), which was administered to a subsample to confirm the presence or absence of psychiatric disorders. Results: In the first stage, N = 924 participants were screened with n = 226 receiving follow-up interviews. The overall prevalence of any psychiatric disorder was 36.3% (39.2% for children and 34.1% for adolescents). For the overall sample, behavioral disorders were more common than emotional disorders (25.7% vs. 21.7%). The most common specific disorders were oppositional defiant disorder (15.9%), attention-deficit/hyperactivity disorder (8.4%), general anxiety disorder (7.8%) and separation anxiety (7.8%). Only having internet in the house and the mother’s education were predictors of having psychiatric illness among the adolescents, but these were not predictors among the children. Conclusion: The rate of psychiatric disorders among Saudi children and adolescents is within the wide range reported by international studies, but is associated with specific social predictive factors.