Ample evidence has been generated regarding the effectiveness of school-based mental health interventions as part of the continuum of care for children and capacity building of teachers to deal with the emotional and behavioral challenges of students. The increasing trend of utilization of teachers as the natural support system of children and the huge financial impact of public health interventions highlights the need to review all available evidence regarding multilevel factors that facilitate or pose a challenge to the provision of School Mental Health Programs (SMHP) using teachers as providers. The current review aims to map extracted evidence under the Consolidated Framework for Implementation Research (CFIR) domains to support future implementation research on school-based mental health services. The scoping review included experimental, qualitative studies, and systematic reviews involving teacher-led mental health programs conducted in the school setting to improve the socio-emotional well-being of children and adolescents irrespective of time and geographical limitations. All (published and unpublished) evidence in English from Pubmed, Cochrane database of systematic reviews and clinical trials, Scopus, and Science Direct was searched using keywords and Boolean combinations and extracted using study designs, place of study, year of publication, sample size, and target population. A qualitative analysis of implementation facilitators and barriers cited by the studies was carried out and mapped on CFIR. This review identified barriers and facilitators of implementation across school-based mental health Programs in 29 studies. The major emerging themes were those related to the inner setting of the organization, the process of implementation, and the characteristics of individuals involved in implementation. These included the availability of structural characteristics, positive school culture, organizational readiness, committed leadership, and beliefs of the providers. Findings highlight the need for early assessment of contextual factors acting as barriers and facilitators and careful execution following realistic planning and stakeholders' engagement to ensure the success of SMHP.