Otto Heinrich "Pim" Frank (12 May 1889 – 19 August 1980) was a German-born Jewish businessman and the father of Anne and Margot Frank. With the rise of Nazism, Frank arranged for his family to go to the Netherlands in 1933. They were unable to leave Europe before Germany invaded in 1940. He and his family, along with four other Jews went into hiding in 1942, living in a hidden annex of the business Frank had formerly owned until the group was betrayed in 1944. The whole group was taken into custody and sent to concentration camps. Otto Frank was the only one to survive the Holocaust. After his liberation, his secretary and rescuer Miep Gies gave Otto the diary Anne had kept during their seclusion. He arranged for the publication of the diary in 1947, and oversaw its transition to the stage and screen.
Otto Frank, his family, and four fellow Jews were able to hide for the duration of World War II emerging from their hiding place, the Secret Annexe, only after the Netherlands were liberated in 1945. The eight people quickly dispersed, and the Franks saw each other little after that. Otto and his wife moved to Switzerland.