Mauritz Adelaar was married and divorced. He and his wife had one child, Emile Herman. Mauritz's ex-wife survived the war. The family lived in Amsterdam. Mauritz Adelaar was the headmaster of a state primary school and was involved in the resistance. On 28 August 1944 he was arrested in Rotterdam and deported via Westerbork.
NIOD, Erelijst Verzet en Koopvaardij, database made by J.W. de Leeuw;
B. Braber, Zelfs als wij zullen verliezen. Joden in verzet en illegaliteit in Nederland 1940-1945 (Amsterdam, 1990) 144-145
Mauritz Adelaar is also commemorated on Jewish Monument Zaanstreek