Recent interventions suggest that the discipline of international relations has moved beyond “grand theories” and “great debates” toward middle range theorizing and quantitative hypothesis testing. At the same time, scholars argue that the field is fragmenting into insular camps. I subject these claims to an analysis that borrows from scholarship on the sociology of science. I apply network analytical methods to dissect the structure of the discipline: its dominant camps, the relationship among them, and their relative role in the discipline. I identify several citation camps, primarily delineated by theory, but also methods and subfields. The realist, liberal institutionalist, and constructivist camps continue to occupy a central role in the field. All three “isms” are identifiable as separate communities. But they are also more closely intertwined and cross-contaminated than the fragmentation thesis suggests. At the margins of the isms, connecting via constructivism, we find three theoretical camps: post-structuralism, English School, and neo-Marxist critical theory. Separate from the theoretical region, we find two camps of formal modeling, methods, and quantitative studies of inter- and intra-state conflict. The most-cited works in the field include both those engaged in grand theorization and quantitative hypothesis testing, but it is still the theoretical camps, the three isms in particular, that give international relations its distinctive sociological structure.