Online brand communities (OBCs) were developed as a digital initiative to increase communication and closeness between followers, loyal customers, and brands, and to establish customers’ long-term and sustainable trust in brands. As digital media increase their reporting of sustainability movements and initiatives, online communities are attracting members who extend the responsibility of sustainable practices to fashion and luxury brands. Fashion and luxury OBCs play a dual role in sustaining customer engagement with brands, and in establishing and circulating various values and practices of sustainability in the fashion and luxury industry. This necessitates that fashion and luxury marketers direct their attention to integrating sustainability marketing into an OBC and motivating customer engagement in these initiatives. This chapter discusses the interface between fashion and luxury consumers and brands to establish awareness and reinforce the importance of sustainability in the fashion industry through OBCs.