Kees van Beijnum (born Amsterdam, 21 March 1957) is a Dutch writer. He grew up in Amsterdam, where his mother had a bar near the Zeedijk. Before he became a writer, he was a journalist. He made his debut as a novelist in 1991 with Over het IJ, a non-fiction novel about a murder case in Amsterdam. He received the Ferdinand Bordewijk Prijs in 2001 for De Oesters van Nam Kee ("Oysters at Nam Kee's").
Van Beijnum also wrote the scenarios for De langste reis ('the longest travel', 1996), a movie about the kidnapping of businessman Gerrit Jan Heijn, and for De Heineken Ontvoering ('The Heineken Kidnapping', 2011), a movie about the kidnapping of Freddy Heineken.