In the contemporary age of global capitalism, international taxation – the taxation of income earned from cross-border economic activity – has become a high-stakes issue. International taxation touches upon the foundations of modern society as an arena for struggle between nation-states and other stakeholders concerning government revenues, economic markets, political ideas, and – above all – social change. However, most existing research on international taxation and, indeed, on the global political economy at large, is dedicated to studying the effects of stable structures and sees change through periodic snapshots of evolving orders. As a result, the dynamic processes enabling and governing change remain underexplored. This dissertation promotes a change-oriented approach to studying complex international contexts that unites insights from International Political Economy on global political-economic orders and from Sociology on micro-social struggles over power and authority. These insights enable an analysis of the dynamics of change in international taxation, and I set out a conceptual language emphasizing the modes, contexts, and sources of change . To develop my analysis, I apply a relational, qualitative and case-based methodology to study developments in international taxation across four levels: Global tax governance, the transnational field of corporate taxation, expert policymaking, and professional practice. I find that systemic change is underway in the core institutional foundations of global tax governance, namely an expansion of multilateral cooperation, institutionalized enforcement, and sovereignty-pooling by states. These changes are entwined with changes in state activism, geopolitical shifts, austerity, populism, and economic transformations. Those broad political changes reverberate in the transnational field of corporate taxation, which has seen a swift ascent of critical activist influence, politicization, destabilization of the dominant professional-technical logic, and increasing conflict over established social hierarchies. Expert policymaking has largely resisted the challenges of critical outsiders, but its historical isolation from popular politics and new expert resources is under scrutiny, opening possibilities for new patterns of influence in technical expert proceedings. In professional practice, the core of everyday work remains remarkably stable despite, and because of, broader social change, as professional identities are entwined with transnational (political) institutions.