Introduction: Nutrition education (NE) is a promising intervention in promoting behavior change. However, in developing countries where it is not included in the national curriculum, many barriers arise. The study aimed to explore the teachers’ perceived barriers of implementing a nutrition education program for adolescents in rural Indonesian schools. Methods: A qualitative participatory action research approach was applied in three selected schools in Bogor, Indonesia. Focus group discussion was used as the main method of data collection, involving 12 teachers who have implemented the Health and Nutrition Program for Adolescents. Triangulation was conducted through observation and feedback questionnaire from students. Data from multiple sources were coded, categorized, and thematically analyzed. Results: Three themes and six subthemes emerged, these include 1) capacity of teachers (lack of training and lack of nutrition knowledge), 2) school support (time constraints and lack of funding), and 3) external environment (unhealthy street vendors and parent’s lack of nutrition awareness). These identified barriers could be minimized by establishing a strong commitment of school principals, the inclusion of street-food vendors and parents, and also ensuring sufficient training of teachers. Conclusion: This study highlights the need for schools and program implementers to identify potential barriers prior to commencing NE and also strengthen opportunities within it. The barriers found in this study emphasizes the need for advocacy, sufficient training of teachers, and consideration of the external food environment. Further studies are suggested to confirm these findings, involving more informants and different settings, such as in the urban population.