NC Gemeinschaft Kraft durch Freude (German for 'Strength Through Joy'; KdF) was a German state-operated leisure organization in Nazi Germany. It was part of the German Labour Front (German: Deutsche Arbeitsfront), the national labour organization at that time. Set up in November 1933 as a tool to promote the advantages of Nazism to the German people and internationally, while also being utilized to ease the process of the rearmament of Germany. It was also intended to compensate for the poor increases in wages and for the loss of trade union rights. Through its structure of organized events and promotion of propaganda, it was also intended to prevent dissident and anti-state behavior. By 1939, it had become the world's largest tourism operator.

KdF was composed of several departments with their own specific goals, with each department organizing different leisure activities. It organized activities such as sporting events on factory floors, art exhibitions, discounted concerts and, most famously and popularly, subsidized holidays and cruise trips. One of its largest departments, although sometimes considered a separate organization altogether, was Beauty of Labour, which concerned itself with physical and sanitary improvements of the workplace. KdF was responsible for the improvement of several factories and sports facilities throughout its operations in the 1930s.

KdF was supposed to bridge the class divide by making middle-class leisure activities available to the masses. It also sought to bolster the German tourist industry, something it did successfully up until the outbreak of World War II. Official statistics showed that in 1934, 2.3 million people took KdF holidays. By 1938, this figure rose to 10.3 million. With the outbreak of war in 1939, most of the organization's programs were suspended and several projects, such as the Prora holiday resort, were never completed.