The present study aims to verify if and which didactic and interactive strategies implemented by teachers in the classroom, during their lessons, can be a factor related to good teacher-student relationships, as well as a factor related to the development of satisfying relationships among peers. The participants in the study were 201 students. Lessons, conducted on ecological topic, were handled by 15 teachers in 3 different countries. In addition, 17 observers, suitably trained and coming from the different countries involved, attended the lessons. Lessons' evaluation was carried out through a toolkit (Toolkit for lesson evaluation), which consists in three different forms related to the point of view of different participants: external observers, students and teachers. Students have completed two tools: the SGE Student Grid and the TEP-Q Etero Evaluation. Observers completed the SGE Observer Grid. The multiple regression analysis suggests that teachers' explanation modality, perceived by the observers, positively predicts the good relationships between teachers and students. Furthermore, teacher's effective communication and teacher's attention to the relationship predict good relationships among peers. Finally, the correlation analysis highlights how good relations between students are related with the use of active methodologies by the teacher.