The status and role of group music performance in Irish secondary schools presents a scenario with contradictory trends. While group music-making ranks as an educationally and socially enriching activity, evidence suggests that in this context, it occurs more often outside rather than inside music classrooms. This study examines the inclusion of such pursuits relating to the activities of composition, listening and performance as outlined in the Irish Leaving Certificate examination syllabus. A two-part research design comprises focus group meetings with practising music teachers followed by action research in Irish second-level schools. Initial findings from the group discussions inform the planning of music lessons involving group performances designed by the researcher and teacher participants. A series of tri-partite and cyclical lesson plans begins with the exploration of musical ideas through group music-making. These ideas are performed while students listen, formulate and offer critical response to the group performances of their peers. Emergent findings from the action research are interpreted through Wenger's theories of learning, Lerman's theory of critical response, Csikszentmihalyi's conceptions of'flow' and enjoyment, and Barthes' concept o f'jouissance'. The first set of findings reveals the flexibility of classroom group music-making as a learning pursuit, outlining its multifaceted contribution to the integration of performing, listening and composing activities. The second set of findings demonstrates how group performing stimulates developments in musicianship and social skills, alongside new classroom management strategies. The third set focuses on experiences of 'jouissance' and 'flow' in group performance, revealing the potential of such activities to engender heightened and memorable awareness during optimal instances of musical concentration. The thesis concludes by way of a critique of current music syllabi in the light of the research findings and highlights the potential benefits of adapting emergent research pedagogies to future studies as well as to music curriculum development.