The fashion industry, the world's third-largest manufacturing sector, is a complex network involvingcreation, production, distribution, and consumption of fashion products. Despite extensive research onsustainable transitions in supply chains, little attention has been given to the role of supply chain actorsin sustainability, especially yarn mills and manufacturers. This thesis investigates the sustainabilitytransition within fashion supply chains with a specific focus on knitwear and textile production in thePrato textile Industrial District (Italy), characterized by its interconnected small and medium-sizedenterprises, which evolved from wool production to a diverse fashion hub. This research aims tounderstand the role of knitwear and woven producers in sustainability transition, exploring drivers,barriers, and sustainability identification. To address this gap, semi-structured interviews wereconducted with members of four different companies, and company sustainability reports andcertifications were also analyzed. The theoretical foundation integrates the Triple Bottom Line (TBL)concept, organizational change, and network theory to explore economic, social, and environmental aspects, fostering a holistic approach to sustainability. Organizational change models like Lewin's three-step model and Kotter's 8-step change model inform the investigation of sustainable organizational practices. Thematic analysis uncovers key themes surrounding sustainable transition, spanninghistorical context, sustainability definitions, sustainability practices, barriers, drivers, and sustainabilitypartners. These themes are linked to organizational change and Network theory in the axial codingprocess, illustrating connections between theory and empirical findings. A conceptual framework isdesigned to link fashion companies' strategies with triple bottom line (TBL), highlightingmanufacturing processes and strategic approaches towards sustainability. Key themes includegovernance, material sourcing, transparency, partnerships, diverse practices, and categorizing driversand barriers. This study contributes to understanding how economic, social, and environmental factorsintersect in fostering sustainable fashion practices. The findings also provide valuable insights intoorganizational change theory and network theory's applicability in sustainable fashion contexts.Recommendations for future research include broader industry scopes, technology impacts, governmentpolicies, and longitudinal studies to track evolving perceptions and practices. The analysis enriches thediscourse on sustainable fashion manufacturing and guides further research endeavors in the fashionindustry's sustainability domain.