Self-efficacy is an individual's belief in and judgments about their capacity to execute behaviors necessary to produce a desired performance. Passive learning and low self-efficacy in the music classroom can lead to student burnout, decreased participation, and often an end to the pursuit of further music education. This research aimed to determine whether self-assessment could be used as a tool to increase capacity for self-efficacy and in turn, autonomous motivation in 9-12th grade music students. This study examined the dynamics among self-efficacy, feedback, and intrinsic motivation in 203 high school music education students in a rural, midwestern 3A public school. Drawing upon self-determination theory, all study participants took a pre-assessment to gauge their baseline level of autonomous motivation. Regular application of self-assessment rubrics in experimental groups throughout the study was used to facilitate metacognitive processing in learners to create awareness of their own thoughts, behaviors, and orientation to learning in the music setting. Intentional questioning strategies designed to build musical self-awareness were integrated into instruction in the third experimental group. Informal interviews captured qualitative data surrounding self-efficacy in the study population. A post-assessment was then given at the end of the study to provide a quantitative measure of student growth in autonomous motivation. The research findings will inform future research and best practice in the field of learning motivation.