Henri Johan "Hans" de Koster (5 November 1914 – 24 November 1992) was a Dutch politician and diplomat of the People's Party for Freedom and Democracy (VVD) and businessman. De Koster attended a Gymnasium in Leiden from May 1927 until June 1933 and applied at the University of Amsterdam in June 1933 majoring in Economics obtaining an Bachelor of Economics degree in June 1935. De Koster worked as a corporate director for the flour manufacturer De Koster & Co in Leiden from April 1937 until May 1940. On 10 May 1940 Nazi Germany invaded the Netherlands and the government fled to London to escape the German occupation. De Koster joined the Dutch resistance against the German occupiers and founded and led the resistance cell Peggy. Following the end of World War II De Koster worked as a civil se