The document summarizes the Addis Tax Initiative agreed upon at the Third International Conference on Financing for Development. The initiative is a partnership to improve domestic resource mobilization by encouraging donors to increase funding for tax systems and developing countries to raise tax revenues to fund development goals. Several countries and organizations have signed on to the initiative and some progress has been made through diagnostic tools and programs in countries like Rwanda and Afghanistan. Other related efforts on base erosion, tax incentives, and private sector participation are also discussed.