Post-colonial critiques of development reveal the neo-colonial potential of the development project, embedded in the imbalances of power in relations between West and East, First World and Third World. One of the core responses to the challenge of such a critique has been to turn to new participatory approaches that privilege local knowledges, locally defined needs and priorities, above the vagaries of aid agencies or the 'expertise' of development professionals. In this paper I argue that such a shift in development discourse and method has had a significant impact on the discursive practices of professionalism and professional responsibility. Drawing on ethnographic research with development professionals in northern Thailand, I argue that participation has emerged as a new orthodoxy among development professionals who seek to identify themselves as ethical and moral agents of an emancipatory development project. The rise of such orthodoxy has had clear impacts in terms of fostering the emergence of local organization and advocacy groups. At the same time, however, this paper considers how a 'pro-local' orthodoxy may also be having dis-enabling effects for the very project of emancipation that professionals wish to carry out.