Abstract. Economic nationalism has been regarded as a set of attitudes rather than a coherent theory. However, by using Durkheim's analytical framework and bringing the concept of the nation into political economy, the author argues that economic nationalism can be provided with a systematic theory. This theory for economic nationalism helps us to grasp the reciprocal relationship between the political and economic power of the nation-state. Economic modernisation, especially industrialisation, needs the powerful state, and the state derives its power from the nation. Economic development can amplify the social imaginary of the nation by expanding mobilisation and communication. Protectionism, industrial policy and Keynesian policy can strengthen not only the economy but also nationalism. The proposed theory for economic nationalism thus paves the way for understanding the role of nationalism in political economy.