Dionysius Adrianus Petrus Norbertus Koolen

Dionysius Adrianus Petrus Norbertus Koolen (21 January 1871, Rijswijk – 24 March 1945, Voorschoten) was a Dutch politician. He was a member of the General League of Roman Catholic Caucuses and its continuation, the Roman Catholic State Party. He was a member of the House of Representatives of the Netherlands from 1905 until 1925, when he became minister of Labour, Trade and Industry, which was a single ministry at the time. He was speaker of the House of Representatives of the Netherlands in the period from 14 October 1920 to 5 August 1925. After being a minister he became a member of the Council of State.