Andries Koekoek was a son of Simon Koekoek and Naatje Fresco. He married 3 November 1915 in Den Haag Mietje Lens, a daughter of Elias Lens and Rachel Prins. The couple had one son, Simon.
Municipal Archive of Den Haag, certificate of marriage of Andries Koekoek, 1915 Series A nr. 854, his family registration card from the People’s Registry.and the Register of Foreigners of the City of Antwerp, nr. 167352, image 326.