Background <p>The concept of health-promoting schools, initiated by the World Health Organization, aims to move beyond individual behavior change and includes changes in the organizational structure, such as improvements in the physical and social environment of the school. By integrating health promotion into all aspects of life, health-promoting schools aim to equip students with the knowledge, skills, and supportive environment required to make healthy choices and develop lifelong healthy behaviors. The present study will aim to apply the social-ecological model in establishing health-promoting schools and improving healthy eating behavior in female students on the basis of social cognitive theory (SCT) in Bastak County, Hormozgan Province, southern Iran.</p> Methods <p>The present exploratory mixed-methods study will be conducted in four phases: qualitative, instrumental, cross-sectional, and interventional. The qualitative phase will continue until data saturation. On the basis of the concepts that will be extracted in the qualitative phase, the SCT questionnaire will be designed and psychometrically validated. In the cross-sectional phase, effective factors for establishing a health-promoting school and promoting healthy eating behaviors will be identified, and in the intervention phase, necessary interventions will be designed in accordance with health promotion strategies and will be implemented in the selected school serving as the intervention group. To evaluate the impact of the intervention, both intervention and control groups will be assessed in terms of healthy eating behavior before and 3 months after the intervention. The social-ecological model will be employed as the guiding framework for the development and implementation of school-based health promotion interventions throughout the study.</p> Discussion <p>The aim of this study will be to design a program to establish a health-promoting school and improve healthy eating behaviors in students on the basis of the Health-Promoting School Checklist and the SCT model. The social-ecological model will also be used as a guiding framework in the design and implementation of the school-based interventions. The outcomes of this intervention will contribute to a deeper understanding of the factors that will influence the promotion of healthy eating behaviors in students. The findings will be effective in the process of developing health-promoting schools and fostering healthy eating behaviors in adolescents.</p> Trial registration <p>Iranian Registry of Clinical Trials IRCT20241123063812N1. Registered on 14 May 2025.</p>