Music self-concept integrates perceptions, beliefs, and self-schemas about a person’s musical abilities and potential. Like other self-concept dimensions, it is multifaceted, hierarchically organized and has implications for motivation toward musical practice. The Music Self-Perception Inventory (MUSPI) is a theoretically-based instrument assessing six specific music self-concept dimensions, as well as global music self-concept. Nonetheless, its applicability is limited by its length (84 items) and by the fact that it does not provide a way to control for consistency biases in the context of repeated measurement. In this study, we developed and validated two parallel versions (A and B) of the MUSPI, and showed that both yielded equivalent psychometric properties to the original, and were fully equivalent to one another. We also tested whether the MUSPI-A and MUSPI-B psychometric properties generalized (were invariant) across gender and grade-differentiated subgroups. Finally, we examined the convergent validity of the MUSPI-A and MUSPI-B. Results highlighted the psychometric soundness, and equivalence, of the various MUSPI versions on all criteria, and showed that they presented patterns of associations with other constructs equivalent to that observed with the original MUSPI.