Background Psychosocial (e.g., anxiety or behavior) problems lead to costs not only in the healthcare sector but also in education and other sectors. As psychosocial problems develop during the critical period of establishing educational trajectories, education costs are particularly relevant in the context of psychosocial problems among children and adolescents. Objectives This study aimed to gain insights into the methods used for the inclusion of education costs in health economics studies and into the proportion of the education costs in relation to the total costs associated with a condition or an intervention. Methods We systematically searched the PubMed, Embase, SSCI, CINAHL, PsycINFO, ERIC, and Econlit databases in August 2019 for economic evaluations of mental health, psychosocial and educational interventions, and cost-of-illness studies of mental, behavioral, and neurodevelopmental disorders conducted from a societal perspective in populations of children and adolescents. An additional search was conducted in February 2021 to update the review. Results In total, 49 articles were included in the analysis. The most common cost items were special education, school absenteeism, and various educational professionals (educational psychologist). A variety of methods were employed for the identification, measurement, and/or valuation of education costs. The proportion of education costs to the total costs of condition/intervention ranged from 0 to 67%, with the mean being 18.5%. Discussion Since education costs can constitute a significant proportion of the total costs of an intervention or condition, including them in health economics studies might be important in informing optimal resource allocation decisions. Although various methods are available for including education costs in health economics studies, further research is needed to develop evidence-based methods for producing comparable estimates.