Using Ezra Schabas’ (1966) report on Ontario community orchestras as a catalyst for inquiry, this dissertation examines the nature of amateur orchestras, arguing that they may be reconceptualised as unique, socio-musical communities of practice through an exploration of several factors which influence their health and sustainability. These include: aspects of amateur musical engagement; the relationship between amateur musicians and the various professional actors found in the amateur context; the importance of ensemble-based music education as a crucible for the development of individual artistry, life-long musical learning, and a socio-musical skill set which will encourage and enhance future orchestral participation; the adoption of new, creative and collaborative practices as pathways to improved socio-musical awareness and artistic freedom; and an approach to public engagement which celebrates diversity, embraces cultural democracy, and fosters community cohesion among players and the public. These concepts are explored against the backdrop of two contrasting paradigms of practice: the traditional symphony orchestra and Community Music. This comparison suggests a new paradigm for amateur orchestras, embodying the characteristics of amateurism, socio-musical cohesion, and community engagement, which can properly be described as “community orchestras.