The objective of this paper is to outline a conceptual model of vulnerability to climate change as the first step in appraising and understanding the social and economic processes which facilitate and constrain adaptation. Vulnerability as defined here pertains to individuals and social groups. It is the state of individuals, of groups, of communities defined in terms of their ability to cope with and adapt to any external stress placed on their livelihoods and well-being. This proposed approach puts the social and economic well-being of society at the centre of the analysis, thereby reversing the central focus of approaches to climate impact assessment based on impacts on and the adaptability of natural resources or ecosystems and which only subsequently address consequences for human well-being. The vulnerability or security of any group is determined by the availability of resources and, crucially, by the entitlement of individuals and groups to call on these resources. This perspective extends the concept of entitlements developed within neo-classical and institutional economics. Within this conceptual framework, vulnerability can be seen as a socially-constructed phenomenon influenced by institutional and economic dynamics. The study develops proxy indicators of vulnerability related to the structure of economic relations and the entitlements which govern them, and shows how these can be applied to a District in coastal lowland Vietnam. This paper outlines the lessons of such an approach to social vulnerability for the assessment of climate change at the global scale. We argue that the socio-economic and biophysical processes that determine vulnerability are manifest at the local, national, regional and global level but that the state of vulnerability itself is associated with a specific population. Aggregation from one level to another is therefore not appropriate and global-scale analysis is meaningful only in so far as it deals with the vulnerability of the global community itself.