Tim Callen is a visiting fellow at the Arab Gulf States Institute in Washington. Callen is a former assistant director in the Middle East and Central Asia department at the International Monetary Fund. He served as the IMF’s mission chief for Saudi Arabia and as the chief of the Gulf Cooperation Council countries’ division from 2012-21. He was responsible for the IMF’s engagement with the government of Saudi Arabia and for the institution’s research and publications on the country. He also led the IMF’s research program on the GCC region. From 2021-22, he served as special advisor to the executive director for Saudi Arabia at the IMF’s Executive Board. Callen’s research interests focus on oil exporting countries and include prospects and policies for economic diversification away from oil, frameworks and institutions to limit procyclical fiscal policy, and appropriate exchange rate policies. Callen joined the IMF in 1993 and also worked in the Asia and Pacific, Communications, and Research departments. Before joining the IMF, he worked in the Economic Departments at the Bank of England and the Reserve Bank of Australia and at Hambros Bank. He holds a bachelor’s in economics from the University of Essex and a master’s in economics from the University of Warwick.