Recent works on 'uneven and combined development' (UCD) have focused on its contributions to the study of political economy and geopolitics, but they have yet to systematically address the cultural dimension of social changethe socially shared ideas by which people understand and act upon the world. The present article addresses this lacuna by applying the premises of UCD to the nineteenth-century emergence of Occidentalism: the idea of 'the West' as the dominant site of culture, civilisation and modernity. Against the problems of methodological internalism and Eurocentrism, I argue that the categories of unevenness and combined development provide critical entry points for an examination of the international construction of 'Western' identities and discourses during the late-nineteenth century imperial era. Specifically, I advance a theory of geocultural feedback which locates the constituting terms of those identities and discourses in a specific conjuncture of global unevenness: how the experience of 'relative backwardness' in late-industrialising societies translated into self-consciously 'Westernising' projects of catch-up development which destabilised prevailing conceptions of white European supremacy. In both the British and American empires, this historical dynamic produced a distinct pattern of cultural transformation: a reactive discourse of civilisational closure centred on the defence of 'the West.' I am especially grateful to my supervisor, George Lawson, for his advice and support throughout the PhD from which this article arises. Thanks also to Justin Rosenberg, the editors of CRIA, and three anonymous reviewers for convening this special issue and providing invaluable comments and suggestions. I would also like to thank Grace Benton and Lewis Bassett-Yerrell for their insightful comments on an earlier draft.