School-based health education has the potential to inform and educate young people, in order to promote healthy behaviours among them, which will help to prevent diseases and social problems. The present study gives an overview of several ethical issues which must be considered in different phases of school-based smoking prevention programs. This will help health educators, public health professionals and researchers in their activity of health education in schools. The ethical issues must be taken into consideration during all the activities and refer to the involvement of officials, schools, parents, young people who participate into the program, authors and persons/institutions responsible with the implementation, evaluation or funding of the programs. The application into practice of these ethical principles, influence the quality of the health education, its acceptability BY the target group and the correctness of results. Also, it prevents possible problems and misunderstandings between persons and institutions involved in the health education and smoking prevention process, which could seriously affect and even destroy implementation of such health education activities.