This thesis examines what happens when the worlds and knowledges of war, international development, and music education intersect. It investigates the practices and experiences of music interventions, a term used in this thesis to describe structured programs for music learning and participation in places that have been unmade by war, taking shape within the structures and funding arrangements of largescale international aid and assistance. It explores the work of three specific music interventions—the Pavarotti Music Centre in Bosnia-Herzegovina, Hadahur Music School in Timor-Leste, and the Afghanistan National Institute of Music in Afghanistan—with the goal of identifying how these kinds of projects are shaped, and their potential for sustainability in a volatile and mutable environment. These case study sites offer interesting contrasts of timeframe (longevity of the music intervention and retrospective distance from the wartime experiences); scale (of ambition, funding, and external drivers); and approaches to the teaching and learning of music, in particular their efforts to regenerate local music traditions. The research was designed as an ethnographic, multi-sited, multi-case study project. Semi-structured interviews and document review were the principal data sources, offering diverse perspectives that bring both positive and critical voices of participants and local community members to the fore, alongside those of organisers and practitioners. Data were coded and analysed thematically, using grounded theory methods. As a result of this process, the thesis argues that the phenomenon of music interventions can be understood as evolving across six critical junctures—sites of negotiation between the various actors—that produce decisions and actions that critically shape each project. The critical junctures—Aims and Motivations, Buildings and Facilities, Pedagogy and Learning Materials, Organisational Culture, Internal Engagement, and External Engagement—also have implications for sustainability, as they represent points of active interface between contrasting constructs and ideals, and therefore can generate instability and conflict as well as harmony and growth. The critical junctures model offers practitioners and scholars a tool for understanding, planning, operationalising, evaluating, and handing over music interventions in waraffected contexts. It sheds light on internal practices, and helps to reveal the influence that the complex wider context can have on shaping and sustaining the music activities. The model of critical junctures for shaping and sustaining music interventions is the central theoretical contribution of this research. In addition, the thesis makes methodological, empirical, and practical contributions to what is a nascent subject of inquiry, mapping three radically different music interventions in their achievements and their missteps, and presenting empirical data from multiple perspectives. In a world that is as much at war as ever, and an aid environment that is increasingly recognising the importance of cultural development and creative expression to human development, this study has deep and immediate relevance to an audience of music and development practitioners, policy makers, and scholars in the fields of (applied) ethnomusicology, music education, community music, music sociology, music therapy, cultural development, and international development.