Purpose: Inspection and evaluation in education gained a different dimension with the implementation of concepts such as accountability, transparency and effectiveness to educational organizations. School self-evaluation is put into practice based on evidence in cooperation with stakeholders in order to develop and improve schools accordingly. The overall objective of this research is to develop a school self-evaluation model supporting school development for public secondary schools. Methods: Among the mixed research methods, multi-stage mixed pattern is used for this purpose. The stages of this pattern are structured in accordance with the Research and Development (R&D) methodology. The documents are examined and the opinions of 9 experts are obtained by means of surveys in order to develop the model draft. Results: A school self-evaluation model supporting school development, which is planned to be implemented annually, is developed in line with the overall objective of this research. This model consists of the following six stages: preparation, planning, implementation, evaluation, taking action, monitoring and reviewing. The first four stages are used for self-evaluation, and the last two stages are for development. The content of the model consists of the following six areas: "administration and leadership, education-training process, school-family-community cooperation, school health and safety, relations and communication at school, professional development". Implications for Research and Practice: In conclusion, a six-stage school self-evaluation model for secondary schools is developed. The model that is developed may be used by adapting it according to the type of school, teaching level and needs. However, the school administrators and teachers need training on basic statistics, research and report writing during the implementation of the model. Experts with postgraduate diploma in fields such as education administration, supervision/evaluation may provide support in this matter. Moreover, opinions may be obtained from field expert academic members, education inspectors, school administrators and teachers regarding the applicability and adoptability of the model that is developed.