The article is devoted to the development of music teachers’ professional competence in the in-service teachers’ training system. The contradiction between the requirement of professional standards for the music teachers’ work and their preparation in the in-service teachers’ training system is discussed. The basic concept of the research - “professional competence” was specified, its structure was analysed, and the content was substantiated. The model of music teachers’ professional competence included such components as key components (informational, regulatory and communicative ones); an operational component; intellectual and educational component. The music teachers doing in-service training course were the participants of an experimental group and a control group. The results of input diagnostics showed the priority of using active forms of study for the experimental group. The detailed description of teaching technologies, used for the experimental group, was presented in the article. They included problem lectures, role games, business games, discussions, etc. The reliability of the output diagnostic results was proved with the help of t-test. The results showed decrease of the number of the music teachers with the low level of professional competence and increase of group members with high level of professional competence. Thus, the findings of the research proves the effectiveness of the model of music teachers’ professional competence.