This study explored the realities of women union activists in order to illuminate their place within the current evolving culture of the labour movement in Canada. Women have been entering the work force and becoming members of unions at increasingly high rates. This increased representation of women union members has challenged the culture of the labour movement and has forced a renegotiation of who is considered appropriate in positions of leadership. The participants in this study were sixteen women members of the Canadian Union of Public Employees (CUPE) who were elected into leadership positions at the local, provincial, and national levels.Literature on womens activism has focused on the barriers facing them and their resultant under-representation in elected leadership positions. However, a comprehensive theory which describes the experiences of women union activists and their personal choices in becoming active has not yet been developed. Using an inductive analysis within a qualitative paradigm, this study explored the multi-faceted experiences of womens lives and how these experiences impact on their desire to become active within CUPE.To explain these experiences, the Self-Fulfillment Theory (SFT) has been developed. The SFT focuses on womens desire to self-actualize and to reach the goal of self-fulfillment as primary reasons for becoming active in the labour movement. Activism is a means for women to develop a sense of personal power and control and ultimately to achieve fulfillment in their lives. Activism is more than a job or a commitment; it is tied to their desired self-perception; namely, as strong competent contributors to society.This study suggests that to explain womens activism within the labour movement, it is important not to focus solely on the barriers limiting womens involvement. An understanding of womens personal desires and feelings about themselves are crucial components for an explanation of womens activism. It is suggested that further work be undertaken to explore the elements introduced within the framework of the SFT. The relationship among self-esteem, self-efficacy and womens activism is a further suggested area of study.