The commercial field of sustainability communications encompasses ground previously demarcated between the fields of Corporate Social Responsibility on the one hand, and marketing, advertising and public relations on the other. This thesis examines the formation and development of this novel field of cultural production and its significance for sustainable consumption and corporate sustainability. The research is orientated by practice theory and draws on participant observation within a sustainability communications agency, interviews and documentary analysis. The heuristic value of practice theory for the study of sustainable consumption is now well established in the context of end-use consumption but is unexplored in the context of commercial sustainability communications. Equally, sustainability communications has been neglected by the field of cultural economy. The key concern is with cultural intermediaries and their capacity or otherwise to instantiate their own mores, understandings and practices in the social world. I address this in terms of sustainability and draw on the idea of performativity to approach commercial sustainability communications as a performative complex of practices. Furthermore, the research aims to problematise the place of 'the consumer' in discourses of sustainable consumption. I produce a genealogy of sustainability communications and an account of the development and contemporary constitution of the associated agency market. I suggest that a defining role that the market plays is the management of the 'strategic ambiguity' of sustainability. Drawing on fieldwork and interviews I identify elements that integrate practices into the complex of sustainability communications and examine its normative orientations. Cultural intermediation is shown to take place through, firstly, the diffusion of practices and practice elements. Secondly, it occurs through attempts to instantiate 'the sustainable consumer'. Models of the consumer at work in sustainability communications are analysed and different modes of instantiation of 'the sustainable consumer' identified. Thirdly, it takes place through articulating sustainability with brands. I explore three arenas in which sustainability communications articulates brand and sustainability: what I identify as the discourse of corporate-sponsored sustainable consumption; the cultural politics of work; and lastly, the public sphere.