Internet governance has rapidly shifted from a technocratic area of governance to one characterized by considerable contention. This shift is unprecedented among the large and increasing number of technocratic regimes essential to contemporary global governance, and is of broader interest and significance beyond Internet governance scholars and practitioners. This paper draws on international relations theory to argue that the emergence of contention in Internet governance entails a twofold shift in the nature of the problems posed by Internet governance: first, cooperation problems have emerged where few previously existed; and second, existing coordination problems have become increasingly difficult to manage as a result of a rapidly increasing number of players and heightened distributional consequences. This paper provides four complementary explanations for the shift in the underlying problem structure: extrinsic uncertainty, changing market conditions, declining US dominance in the Internet governance system and social processes of institutional change and regime complex formation.