Introduction. The article concerns research conducted among teachers and principals of primary schools in Poland and the Czech Republic as part of a project co-financed by the European Regional Development Fund and the State budget, We Cross the Borders. The Key Competencies in Teaching and Education project was implemented under the recruitment of the Praděd Microprojects Fund, Priority axis number: 11.4, priority axis name: Cooperation of institutions and communities. Aim. The theoretical and cognitive aim of the research was to diagnose the competencies of teachers and principals in critical thinking. The practical-implementation objective of the research was to develop practical recommendations that may be included in the education programs of future teachers and principals. Methods. The research used the method of a diagnostic survey and the questionnaire technique. Data analysis was performed with the use of STATISTICA software. Results. The research results showed differences between the behaviour of teachers and principals in such matters as contact with parents, following the headmaster’s instructions, using innovative teaching methods and self-confidence in everyday work-related situations. The results show statistically significant differences in their declarations of behaviour in a particular situation. From the research, it can be concluded that principals are more interested than teachers in solving any difficult situation to resolve the conflict rather than focusing primarily on the consequences of the situation.