To make a business case for corporate sustainability, firms must be able to sell their sustainable products. The influence that firm engagement with non-governmental organizations may have on consumer adoption of sustainable products has been neglected in previous research. We address this by embedding corporate sustainability in a cosmopolitan framework that connects firms, consumers, and civil society organizations based on the understanding of responsibility for global humanity that underlies both the sustainability and cosmopolitanism concepts. We hypothesize that firms’ sustainability engagement (...) and their NGO engagement influence consumer adoption of sustainable products. Empirically, we investigate the adoption of sustainable Eco-circle products made from recycled fibers marketed by Li Ning, a China-based global sportswear brand. We apply a stepwise regression approach to test our hypotheses with paper-and-pencil survey data from 217 Chinese consumers. We find adoption to be positively associated with consumers’ sustainability attitude but not with firms’ sustainability engagement. For firm–NGO engagement, these relationships are reversed: Adoption is positively associated with firm–NGO engagement, but not with consumers’ related attitude. Our results present a picture of the Chinese context in which there is a business case for corporate sustainability if firms’ words about sustainable product strategies are supported by signals from civil society about firm deeds. The results imply that in a Chinese context, firms need to be particularly aware of the role of NGOs when hoping to be rewarded for sustainability. (shrink)