Carrying out a research within the field being a part of a meta-science, which has the object of the whole education system with relevant educational processes at different levels, educational institutions, factors, dominant and trends in its development, resources, including human capital, and other elements together with the mechanisms of interaction between them, we use the term "educational comparative studies" as more adequate to define the research field mentioned above. It is stated that modernization of the national educational system in Ukraine in the framework of the world mainstream is not possible without unified and well-defined terminological bases, methodological foundations, principles and criteria for comparative studies that meet the current level of the science development and the needs of society. It is proved that the most effective way of fulfillment a comparative analysis of education systems in different countries is a detailed study of theory and practice of their teachers' preparation for the systems under consideration. Having analyzed different scientific approaches to identifying criteria for a comparative study, the criteria on the development of teachers' preparation are introduced. It is highlighted that the defined criteria will be applied in the research work on the development of special education teachers' preparation systems in the USA, the UK and Ukraine. They are introduced in the article: legal support of the educational system for individuals with special needs; national and regional standards of special education teachers' preparation; curriculums, methods, and technologies for special education teachers' preparation; system of retraining and licensures of special education teachers; informative and scientific subsystem of special education system; subsystem of special education teachers' pre-service preparation and in-field practical work management; financial and economic subsystem of training and retraining of special education teachers.