Barend Koopman was the son of Levie Koopman and Debora Vogel. He was married twice. After he divorced his wife on 27 November 1935 in Den Haag, with whom he had three children, Barend Koopman married Tresia Blitz on 8 June 1938 in Amsterdam, a daughter of Samuel Blitz and Anna de Swarte.
The couple had one son, Louis.
Amsterdam Municipal Archives; record card of Barend Koopman and Tresia Blitz.