This article explores an overlooked element of Locke’s international thought, namely that political communities emerge out of human sociability, friendship, and trust. The argument developed here diverges from both the dominant, modernist-realist interpretation of Locke, which sees him as crypto-Hobbesian, as well as the liberal-legalist tradition, which sees Locke portraying states as voluntarily complying with a set of normative requirements qua international law. While I think the liberal legalists are on the right track, their approach reduces international agreement to something that is merely rational-deliberate. The way Locke speaks about the formation of political communities is reminiscent of what we now call “security communities,” a term popularized by Karl Deutsch in the 1950s. Even though Locke was writing in less favorable geo-political conditions—prior to the emergence of mature security communities—the trajectory of his thought points to the possibility of integrated global communities based on friendship and trust.