School development planning is an instrument of school internal development. It has been present in Serbian schools since 2002, but until today there have not been enough data regarding the way development planning takes place and what its effects are. The main question in this research is how the teachers directly involved in the process itself evaluate development planning in their schools. The sample consisted of 291 teachers from 51 primary schools in Serbia. They replied in written form to the open-ended questions regarding their opinion about the positive and the negative sides of school development planning. Data processing included creating categories of teacher answers and calculating the relative presence of answers by categories. Teachers estimated that the following were the positive sides of development planning: strengthening cooperation and team work, introducing planning practice, school development, increased participation, successful project realization and acquisition of new knowledge and advanced training. Teachers most often had no objections to development planning, and when they did, these referred to the following: insufficient support to the development team, resistance and lack of interest of their colleagues, demands of planning, problems with the functioning of the development team and poor plan realization. The results point out to the conclusion that school development planning is predominantly positively evaluated and at the same time provide the foundation for arriving at practical ideas regarding the future direction of the policies in the field of internal school development.