Herman Onno Christiaan Rudolf "Onno" Ruding (born 15 August 1939) is a retired Dutch politician of the Christian Democratic Appeal (CDA) party and businessman. Ruding worked as student researcher at the Erasmus University Rotterdam from June 1964 until July 1969 and worked as a civil servant for the Ministry of Finance from February 1965 until June 1971 and as Deputy Director-General of the department for International Monetary Affairs from February 1965 until September 1966 and Director-General of the Department for International Monetary Affairs from September 1966 until June 1971. Ruding worked as an investment banker for the AMRO Bank from June 1971 until January 1977. In December 1976 Ruding was nominated as an Executive Director of the International Monetary Fund (IMF), taking office