Music self-concept measurement tools are essential at all music educational levels in all contexts. Until now, the lack of a validated music self-concept questionnaire in Spanish-speaking countries has been noticeable. The aim of this study is to validate the Musical Self-Concept Questionnaire (CAMU) (Zubeldia, M. 2015. "El autoconcepto musical, motivación y bienestar psicológico del alumnado de conservatorio [Musical self-concept, motivation and psychological well-being of conservatory students]." Doctoral thesis. Leioa: UPV-EHU), which is an abbreviated and culturally adapted Spanish language version of the Music Self-Perception Inventory (MUSPI), developed by Vispoel (1993a. "The Music Self-Perception Inventory (Adolescent Form)." Iowa: Author, 1993b. "The Music Self-Perception Inventory (Adult/College Form)." Iowa: Author). Participants comprised 407 students from mid-level music studies from conservatories located in different autonomous regions of Spain. The confirmatory factor analysis supports the hierarchical view of the music self-concept. Furthermore, the study also tests the scalar invariance across gender-differentiated subgroups, which is a prerequisite to compare factor mean differences between groups. This is the final step in the validation of the CAMU, which enables cross-cultural research into this construct. The educational implications for music students are discussed.