Participatory Music Projects seek to engage people in different forms of music-making, including instrumental music, vocal music, dance and body expression, etc. These projects, understood as socio-educational initiatives aiming at community engagement, are most frequently implemented in non-formal educational settings, with a commitment to providing universal access to music education and to promoting methodologies grounded in the active practice of collective music-making. Nevertheless, in recent years, many of these initiatives have been incorporated into formal educational contexts, leading to the development of major participatory music projects in primary and secondary schools. Musical self-concept is an important predictor of children’s interest in future music participation. The aim of this study is to examine the impact of engagement in participatory music programs on students’ musical self-concept within primary and secondary education. A quasi-experimental pretest posttest design with a control group was applied to 954 Spanish primary (483) and secondary (471) students from 19 schools across the country, using the Musical Self-Concept Scale (Cabedo-Mas et al., in press), a 19-item questionnaire rated on a 5-point Likert scale. The data was analysed using descriptive and inferential statistics, including ANCOVA with SPSS (Version 31). Differences in students’ musical self-concept between the control and experimental group were analysed, together with its correlation with other factors such as gender, age, and participation in out-of-school musical activities. The results indicate that engagement in participatory music projects had an effect on students’ musical self-concept. Possible differences associated with gender, age, and prior musical experience were identified, suggesting that these factors may influence students’ levels of musical self-concept. Overall, the findings highlight the importance of accounting for these variables when developing inclusive and collective approaches within school curricula, as well as when designing strategies that foster students’ motivation and engagement in music education.