This study investigates how Slow Fashion brands communicate core values through Instagram and the impact of these values on audience engagement. Slow Fashion, a movement advocating ethical, sustainable, and socially responsible clothing production, counters fast fashion by emphasizing quality, localism, and environmental consciousness. Employing content analysis on Slow Fashion brands’ Instagram posts, we identify key values, that brands use in their social media communication, such as sustainability, craftsmanship, and ethicality. Post engagement is also measured via likes, comments, and engagement rates. Findings show that posts featuring multiple key values, generate the highest engagement, with sustainability and craftsmanship being the most prominent ones. These insights provide guidance to digital marketers to develop effective strategies for sustainable brands and highlight social media's role in promoting values that resonate with eco-conscious audiences.