This dissertation examines the relationship between associations and democracy in Classical Athens. It seeks to test some of the main hypotheses of modern theorists of social capital in the ancient Athenian context. I argue that civil associations of a certain type and democratic institutions roughly co-vary in Athenian history, and suggest a couple of mechanisms that may have linked the two phenomena. In my main example, I show how Athenians outsourced the task of defining the citizenry to a series of associations. In doing so, they helped minimize their reliance on a central state, dispersing authority and information among a network of small groups.