AbstractInternational institutions, such as the World Bank, the International Monetary Fund and the U.S. Agency for International Development, have been assessing tax system performance and capabilities for decades without having a solid international comparator basis for undertaking these assessments. This article provides a series of indicators and benchmarks that can help to put such assessments into an international perspective, set specific targets for performance, reform and modernisation, and monitor progress over time. Copyright © 2005 John Wiley & Sons, Ltd.