What would it mean to decolonise the concept of war? ‘Decolonising’ means critiquing the ways in which Eurocentric ideas and historiographies have informed the basic categories of social and political thought. Dominant understandings of the concept of war derive from histories and sociologies of nation-state formation in the West. Accordingly, I critique this Eurocentric concept of war from the perspective of Small War in the colonies, that is, from the perspective of different histories and geographies of war and society than were assumed to exist in the West. I do so in order to outline a postcolonial concept of war and to identify some of the principles of inquiry that would inform a postcolonial war studies. These include conceiving force as an ordinary dimension of politics; situating force and war in transnational context, amid international hierarchies; and attending to the co-constitutive character of war and society relations in world politics.