School mental health is a multidisciplinary research field and applied concept focused on promoting the psychological well-being and addressing the mental health needs of students within educational settings. It investigates the prevalence, risk and protective factors, and developmental trajectories of mental health conditions in school-aged populations, alongside the development, implementation, and evaluation of prevention programs, early interventions, and comprehensive support systems integrated into the school environment. Key characteristics include an ecological perspective considering the interplay of individual, family, school, and community factors, and an emphasis on multi-tiered systems of support designed to benefit all students while providing targeted assistance to those requiring it. Its significance lies in its critical role in fostering positive youth development, improving academic achievement, reducing behavioral problems, and creating safe, supportive, and inclusive school climates essential for learning and overall life success.