Willem "Wim" Thomassen (3 October 1909 – 16 June 2001) was a Dutch politician of the Labour Party (PvdA). Thomassen was born in Amsterdam. He was a schoolteacher and during World War II imprisoned by the Germans in Amsterdam from 1943 until January 1944. After the war he was secretary of the Dutch People's Movement from August 1945 until July 1946. On behalf of the Labour Party he was a member of the House of Representatives from July 1946 until July 1948. His wife was also a schoolteacher. Wim Thomassen died at age 91 in Bergen (North Holland).