The article is devoted to the theoretical and methodological aspects of stimulating teachers to professional development and personal and professional self-improvement in the system of postgraduate education. It is taken into account that the main way for pedagogical workers to obtain education is training, self-study based on the rethinking of self-development and self-improvement. Based on the analysis of psychological and pedagogical literature, the essence of the scientific definitions “development” and “self-development” was analysed. Thus, “development” is considered as an active process of personality formation based on improvement. Development involves conscious behavior aimed at improving personal and professional qualities and the desire to achieve effectiveness, increase independence, and the creative nature of activity. “Self-development” is a necessary condition for the self-realisation of an individual, which involves the inner independent desire of a person to enrich their own individual qualities. Active development as well as self-development of teachers is carried out in the system of postgraduate education on the basis of the acmeological approach. The implementation of the acmeological approach increases the need for achievement, motivates teachers to act successfully, promotes them to achieve “acme”. Postgraduate education allows improving objective, subjective, procedural and performance criteria of pedagogical activity. Within the framework of self-development of teachers in the system of postgraduate education, the acmeological approach is based on four main aspects: 1) organising the acmeological environment; 2) establishing the acmeological position; 3) developing the acmeological potential; 4) improving the acmeological culture. Based on the use of the acmeological approach, the following positive achievements were reached: there increased independence in goal setting, which was based on the formulation of strategic and tactical goals, setting practical tasks, choosing effective ways of achieving the defined goal; it became possible to ensure the creative nature of educational activity on advanced training courses as every student independently created the program of their personal and professional development. The article presents a range of educational programs aimed at improving the level of general competences (speech competence, communicative competence, inclusive competence, digital competence, managerial competence, moral and ethical competence) of teachers in the system of postgraduate education at the Postgraduate Education Centre of Ternopil Volodymyr Hnatiuk Pedagogical University. Innovations in the process of organisation of advanced training courses at the Postgraduate Education Centre were analysed. In particular, we mean the organisation of master classes, trainings, roundtable discussions, scientific discussions, international and all-Ukrainian conferences and forums, creative laboratories, methodological workshops, Web-quests, practical simulations, which contribute to increasing teachers’ internal motivation for self-development and self-improvement.