The alphabet agencies, or New Deal agencies, were the U.S. federal government agencies created as part of the New Deal of President Franklin D. Roosevelt. The earliest agencies were created to combat the Great Depression in the United States and were established during Roosevelt's first 100 days in office in 1933. In total, at least 69 offices were created during Roosevelt's terms of office as part of the New Deal. Some alphabet agencies were established by Congress, such as the Tennessee Valley Authority. Others were established through Roosevelt executive orders, such as the Works Progress Administration and the Office of Censorship, or were part of larger programs such as the many that belonged to the Works Progress Administration. Some of the agencies still exist today, while others have merged with other departments and agencies or were abolished.

In the United States, the Great Depression began with the Wall Street Crash of October 1929 and then spread worldwide. The nadir came in 1931–1933, and recovery came in 1940. The stock market crash marked the beginning of a decade of high unemployment, poverty, low profits, deflation, plunging farm incomes, and lost opportunities for economic growth as well as for personal advancement. Altogether, there was a general loss of confidence in the economic future.