Concern has been growing recently in China about the well-being of children, women and the elderly "left behind" on the farm when family members leave the village in search of waged work. Increasingly, the left-behind are portrayed in academic and policy discourse as a "vulnerable group" of passive dependants, sidelined by modernisation and abandoned by their families. This paper challenges this discourse, arguing that while attention to the well-being of the left-behind is vital, there is an urgent need for a shift in focus from their vulnerability to their agency. The paper focuses on the agency of left-behind women between the ages of 50 and 80. It aims, first of all, to point the way toward an empirically richer understanding of the social construction of older women's agency and well-being. The second aim of the paper is to suggest how different conceptualisations of "agency" and "older women" might contribute to more ethical and politically effective strategies for development and the improvement of women's well-being. To further these two aims, the paper draws on fieldwork conducted in rural Ningxia, north-western China, and on critiques of the "capability approach" to development expounded by Amartya Sen and Martha Nussbaum.