(1. University of Ioannina, Greece; 2. Directorate of Primary Education of the Prefecture of Attica, Athens, Greece)

Abstract: The effectiveness of school units is a broad concept and concerns both their staff and the relationship of the unit with the context in which it operates. In the present work, the concept of school effectiveness is investigated, through a bibliographic review. Next, an attempt is made to outline the profile of the effective teacher and to highlight the importance of effective management in shaping the effectiveness of a school unit. Following is an extensive record of the models that have been developed to assess the effectiveness of a school and, finally, issues of increased importance are identified which have a decisive impact on the degree of effectiveness of school units.

Key words: intra-school conflicts, ways to resolve the intra-school conflicts, effective communication in school units, the role of principal in school