Bernard Koopman was a son of Joel Koopman and Dientje de Vries, both from Leeuwarden, who were married in Amsterdam on 20 August 1885. Bernard was the youngest son of a twin; his twinbrother was David who became an upholsterer and who was unmarried. Bernard, also an upholsterer, married Sara Saphier in Amsterdam on 9 March 1919, a daughter of Marcus Saphier and Sophie Hillesheim. The couple had no children.
City Archive of Amsterdam, archive cards of Bernard Koopman, David Koopman and Sara Saphier, family registration card of Joel Koopman and website www.wiewaswie.nl.