Despite recent reviews of the effects of arts therapies and music therapy on people with intellectual disabilities (IDs), significant knowledge gaps remain in this field, notably concerning informal music activities and the role that young participants play in music interventions. A scoping review was conducted in January 2021 to explore music interventions implemented in youth with ID and their effects. In total, 74 studies were retained, including 12 reviews and 62 empirical studies. We apply a bibliometric analysis to identify the evolution of publications and research trends in the field. We then attempt to answer the question: “What is the state of knowledge on music education for youth with ID?”. To do so, we describe the music interventions examined in the research to date and the main measured effects. Overall, the findings show that music interventions in youth with ID facilitate overall development in terms of a range of functional skills, that technology-assisted music training has excellent educational promise, and that learner voice merits greater attention in the music research. Nevertheless, studies have largely neglected to consider self-determination and creativity, qualities that are likely to foster youth engagement, and in the longer term, promote social participation.