This article offers a new interpretation of Kant’s cosmopolitanism and his anti-colonialism in Toward Perpetual Peace. Kant’s changing position has been the subject of extensive debates that have, however, not recognized the central place of colonialism in the political, economic, and military debates in Europe in which Kant was writing. Based on historical evidence not previously considered alongside Perpetual Peace, I suggest that Kant’s leading concern at the time of writing is the negative effect of European expansionism and intra-European rivalry over colonial possessions on the possibility of peace in Europe. Because of the lack of affinity between colonial conflict and his philosophy of history, Kant must adjust his concept of antagonism to distinguish between war between particular dyads, in particular spaces, and with particular non-state actors. I examine the implications of this argument for Kant’s system of Right and conclude that his anti-colonialism co-exists with hierarchical views of race.