Cooperation is crucial in educational context. Erikson says that ‘cooperation is the fundamental key of human development’ (Erikson, 2013, pp. 26-27). Schools are treated as institutions responsible for preparing young people to be self-regulated and responsible human beings able to cooperate for the sake of their own development (Mazurkiewicz, 2014). Head teachers as school leaders initiate and organize these processes. Sennett thinks that cooperation requires the competences, especially social competences - dialogical competences (listening well to each other, finding common views, conflict management etc.) (Sennett, 2013). The paper presents the results of research showing how school heads perceive their competencies that will be taken as a starting point for designing proposals of new type of training for school leaders in Poland. More than 2800 principals of different types of schools were asked to assess their competences in six broad areas. The research aim of this paper is to analyze the perception of cooperation by the principals. The research shows that competences related to cooperation are important for principals and they declare that they have them. We can conclude as well that cooperation with other entities is more important for principals of school located in smaller cities and in villages
