Active school travel is a suitable way to increase the physical activity of students and is an environmentally friendly travel method. Therefore, the purpose of this research was to identify the factors affecting the active travel of students to school. The qualitative research method and Grounded theory using Glaser's approach were used. The statistical population of the research included physical education teachers, physical education assistants of the Department of Education and Training, physical education experts of the Department of Education and Training, faculty members of physical education at Farhangian University, school principals, Officials and decision makers of urban planning, students and parents. Semi-structured and in-depth qualitative interviews were conducted with 14 people who were aware about the research topic, and they were selected purposefully. Interviews were continued until the theoretical saturation. Transferability and verifiability and credibility were used to check the validity, and also the intra-subject agreement method of two coders was used to check the reliability. The results of open coding indicated that 122 factors can be effective in identifying factors affecting active school travel. In the selective coding stage, factors were classified into 23 subcategories. Finally, eight main categories resulting from theoretical coding were identified. The categories include neighborhood safety, social support, cultural support, physical environment that supports active school travel, appropriate education, student participation, positive attitude and use of information communication technology. Officials can use the identified factors, concepts and categories in their future planning to operationalize active school travel.