BACKGROUND The rising percentage of children and adolescents experiencing mental disorders brought attention to the emerging opportunities for proactive oral health interventions in this population. Currently, existing guidelines focus mainly on oral health in general practice and on adults residing in care homes. This report aims to provide a broad overview of the effectiveness of oral health interventions for children and adolescents with mental disorders. METHODS This review followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses 2020) statement. The initial electronic search yielded a total of 3710 articles. The search identified 2354 potential papers after removing duplicates and 2301 articles were excluded by title and abstract. The full texts of the remaining 53 articles and nine articles from the citation searching were screened and 15 articles matched the inclusion criteria. The Mixed-Method Appraisal Tool (MMAT) was used for quality appraisal. RESULTS The thematic analysis resulted in four main themes which were educational intervention, physical intervention, clinical intervention, and a combination of both educational and clinical intervention. CONCLUSIONS We presented the findings in a narrative synthesis with the primary outcomes which served as answers to our main research question that prompted this systematic review.