The National Socialist German Workers' Party, commonly referred to in English as the Nazi Party, was a political party in Germany active between 1920 and 1945 that practised Nazism. Its predecessor, the German Workers' Party (DAP), existed from 1919 to 1920.

Hitler's membership card in the DAP (later NSDAP) Hitler became the DAP's 55th member and received the number 555, as the DAP added '500' to every member's number to exaggerate the party's strength.