Willem Joost "Wim" Deetman (born 3 April 1945) is a retired Dutch politician and teacher who served as Minister of Education and Sciences from 1982 to 1989, Speaker of the House of Representatives from 1989 to 1996 and Mayor of The Hague from 1996 until 2008.

Deetman worked as a researcher for the Protestant Christian Education association (VBPCO) from August 1972 until May 1974.

After the election of 1981 Deetman was appointed as State Secretary for Education and Sciences in the Cabinet Van Agt II, taking office on 11 September 1981.

After the election of 1982 Deetman returned as a Member of the House of Representatives, taking office on 16 September 1982.

Deetman retired after spending 37 years in national politics and became active in the private sector and public sector and occupied numerous seats as a corporate director and nonprofit director on several boards of directors and supervisory boards (ADO Den Haag, ProDemos [nl], Mauritshuis, Parliamentary Documentation Center, HMC Bronovo [nl], Kloosterkerk, Madurodam, Cornelia Foundation and the Institute for Multiparty Democracy) and served on several state commissions [nl] and councils on behalf of the government (Catholic Church sexual abuse Commission and Public Pension Funds APB).