"Arbeit macht frei" is an old German and Swiss-German peasant saying meaning "work liberates" or "work shall make you free". It is part of the concept of the Protestant work ethic.

The slogan was employed by the German Nazi party during the 1930s, at the time when they were instigating a massive national construction policy to counter unemployment.

As either a sign of contempt for Jewish culture or as an ironic joke or satire, or a way of instilling false hope, this slogan was placed at the entrances of a number of Nazi concentration camps. Although it was common practice in Germany to post inscriptions of this sort at the entrances to institutional properties or large estates, the use of the slogan in this particular way was ordered by SS General Theodor Eicke, inspector of the concentration camps. The slogan can still be seen at several sites, including those at Auschwitz I, Dachau, Gross-Rosen, Sachsenhausen, and the Terezin Ghetto-Camp (at Buchenwald, however, "Jedem das Seine" was used instead; English translations of this phrase vary, and include "To each his own" and "Everyone gets what they deserve").

As a consequence, this saying has acquired very negative and sinister under-tones in much of the western world.

In 1938, the Austrian political cabaret writer Jura Soyfer and the composer Herbert Zipper, then both prisoners at Dachau concentration camp, wrote the Dachaulied, the Dachau song. They had spent weeks marching in and out of the gates of the camp to forced work every day, and considered the motto "Arbeit macht frei" above the gates as an insult. The song repeats the phrase cynically as a "lesson" taught by Dachau. The first verse is translated in the article on Jura Soyfer.