In the midst of the educational reform processes in the Republic of Croatia, the dissertation Razvojne perspektive izvannastavnih glazbenih aktivnosti učenika osnovnih škola u Republici Hrvatskoj (Development Perspectives of Extracurricular Music Activities of Primary School Students in the Republic of Croatia) is based on determining the existing state of implementation of extracurricular music activities, but also on finding solutions for the development and improvement of musical and pedagogical practice in the field of extracurricular music activities as a significant and an important part of the school curriculum. The intention of this paper is to offer development guidelines that will respond to the interests of students in relation to various forms of dealing with music in their schools, with the aim of developing and enriching artistic and cultural content of extracurricular music activities. For this purpose, a survey was conducted in all counties (N = 21) in the Republic of Croatia on a sample of (N = 4602) respondents, of which (N = 4240) pupils from grades 5 to 8 from (N = 79) elementary schools and (N = 362) teachers of music. The problem questions of the research have been defined and they were related to examining the existing implementation of extracurricular music activities in the Republic of Croatia. Furthermore, the existing student involvement in extracurricular music activities in schools is measured in relationship with the students' interests to engage in extracurricular music activities with the enriched content. In addition, attitudes and opinions on participation in extracurricular music activities were considered as important indicators of development and improvement in the area, from the student perspective. The general attitudes about music, general attitudes about school, motivation for participation in extracurricular music activities, attitudes about organization and offer of extracurricular music activities, attitudes about the effects of these activities on student achievement, and comprehensive development and attitudes on evaluation of extracurricular music activities were studied. The implementation of extracurricular music activities is also considered from the perspective of the teacher with regard to the role of the teacher in planning and implementing these activities and the possibilities of their enrichment based on the interests of the students. Instruments designed for the purpose of this research are student questionnaire and questionnaire for teachers. Research results point to the limiting factors that need to be addressed as the foundation for future developmental opportunities of extracurricular music activities. Considering the interests of students as the basic principle in creating programs and content of extracurricular music activities and opinions and attitudes of teachers, solutions for a better organization and V implementation of extracurricular music activities in schools in the Republic of Croatia are also proposed. Since the number of elementary school students that also attend music school is relatively small, the scientific contribution of this paper brings solutions for the future developmental opportunities in this area. The developmental opportunities that are suggested should respond to the needs and interests of students and define the guidelines for developing a more contemporary concept of extracurricular music activities and this contribute to the development of educational music practice itself.