Taxation is fundamental to sustainable development. The ability to raise revenue and manage public expenditure is of core importance to every state. However, taxation plays another crucial role which has been often overlooked or underestimated in the past: as a catalyst for more responsive and accountable governments. This article explains why international taxation is a “missing link” in the development-statebuilding process and offers an important route for building effective and self-supporting states. It explores the challenges for developing countries with regard to international taxation and how future work proposed by the OECD will address these challenges. The article concludes with an assessment of what more the international community can do to better target aid towards building the capacity of developing countries’ tax administrations.