In secondary general music classes, adolescent musicianship can be stifled by poor self-efficacy. Although adolescents typically lead lives rich with music, they may believe that these interests and experiences do not apply within school settings, may become preoccupied with images of seeming musical perfection, and may even perceive themselves to be unmusical. Societal messaging and school music programs themselves may unfortunately enhance these views. Four sources of self-knowledge that inform self-efficacy provide considerations and approaches for secondary general music teachers.