This study investigates the work of the performer, composer, educator, music therapist and activist Sharon Katz. Beginning in 1992, Katz made history in apartheid South Africa when she formed a 500-member choir that showcased both multi-cultural and multi- lingual songs in their staged the production, When Voices Meet, which incorporated music, songs and dance, intended to assist in promoting a peaceful transition to democracy in South Africa. The success of the concerts of When Voices Meet led to Katz securing sponsorships to hire a train, “The Peace Train”, which transported 130 performers from city to city with media crews in tow. The performers’ mission on this journey was to create an environment of trust, of joy, and of sharing through music, across the artificially-imposed barriers of a racially segregated society. This investigation includes several areas of inquiry: The South African Peace Train; the efforts of the non-profit Friends of the Peace Train; Katz’s work with Pennsylvania prisoners and boys at an American Reform School; the documentary When Voices Meet, and the American Peace Train Tour of July 2016, bringing the message of peace and harmony through song to racially and socio-economically divided Americans on a route that started in New York and culminated with a concert at UNESCO’s Mandela Day celebrations in Washington D. C. These endeavours are examined within the framework of musical activism. The multi-faceted nature of Katz’s activism lends itself to an in-depth multiple case study. Qualitative case study methodology will be used to understand and theorise musical activism through detailed contextual analyses of five significant sets of related events. These include Katz’s work as a music therapist with prisoners in Pennsylvania and a Boys’ Reform School; as activist with The South African Peace Train of 1993; as humanitarian with Friends of the Peace Train; in making the documentary, When Voices Meet, and as activist with the American Peace Train Tour of 2016. In documenting the grass-roots musical activism of Sharon Katz, I hope to contribute towards a gap in South African musicological history that would add to a more comprehensive understanding of musical activism and its role in social change. / Art History, Visual Arts and Musicology / D. Litt. et Phil. (Musicology)