This chapter reviews the political science and political economy literature on the failures and successes in the regulation of tax haven activities. We organize the review around four main explanatory factors – interests, ideas, power and institutions. Each adds important insight into our understanding of the cleavages and dynamics of the international regulation of tax havens. Further, most accounts converge in the observation, running counter to the majority discourse in the public domain, that the real cleavage is not between normal tax states and tax havens, but capital interests vs. other, wider societal interests. Future research should focus on the historical emergence of tax havens and their domestic politics.