A major problem with the emerging sociological literature on cosmopolitanism is that it has not adequately theorized mechanisms that mediate the presumed causal relationship between globalization and the development of cosmopolitan orientations. To solve this problem, I draw on Bruno Latour’s actor-network theory (ANT) to theorize the development of three key elements of cosmopolitanism: cultural omnivorousness, ethnic tolerance, and cosmopolitics. ANT illuminates how humans and nonhumans of multiple nationalities develop attachments with one another to create network structures that sustain cosmopolitanism. ANT also helps the sociology of cosmopolitanism become more reflexive and critical of its implicit normative claims.