Siebren Erik Hazelhoff Roelfzema DFC RMWO (3 April 1917 – 26 September 2007) was a Dutch wartime RAF-pilot, Dutch spy and writer. He was a Knight 4th class of the Military William Order. In the Netherlands he became famous as the writer of the 1970 book Soldaat van Oranje (Dutch: Soldier of Orange) in which he describes his experiences in World War II, and which was made into a 1977 film directed by Paul Verhoeven and starring Rutger Hauer.