Background. The development of school-based programs for preventing adolescent sexual harassment often lacks an evidence-based approach and use of proper theories. Appropriate stakeholders are often not involved in the development process. To help improve this process, we used the Intervention Mapping framework to retrospectively evaluate the development of two school-based programs, Benzies & Batchies and Boys, each of which was intended to prevent sexual harassment among adolescent students of a lower educational level in the Netherlands. The two interventions were among the first school-based programs targeting sexual harassment, and were implemented in Dutch secondary schools. Methods. As well as doing desk research into the context and content of the interventions, we used semi-structured focused interviews with the initial developers to gather their opinions on and experiences with the development process, whereby the topics were based on the six steps of the IM framework. To better suit the needs of the respondents, we had adapted the language of our topics and had used open-ended questions The data we had gathered from the desk research and face-to-face consultations were checked against a planning tool that was based on 19 tasks within the six steps of IM. Results. Although both programs had been developed in practice and lacked a thorough theoretical foundation, the methods and materials used represented aspects of behavior-change theories. The developers of Benzies & Batchies completed slightly more planning criteria within the six steps of the planning process, and used more change methods than the developers of Boys did. Conclusions. We recommend that parents should also be involved in the development of sex and relationship education programs, and should be allowed to participate in the program itself. To meet the needs of intervention developers, greater insight is needed into the importance of the individual steps in the Intervention Mapping framework. In our view, the development of practice-based interventions will improve if future intervention developers combine evidence-based theories with their practice-based experience. This will increase the success and effectiveness of their interventions.