The eight-hour day movement or 40-hour week movement, also known as the short-time movement, was a social movement to regulate the length of a working day, preventing excesses and abuses.

An eight-hour work day has its origins in the 16th century Spain, but the modern movement dates back to the Industrial Revolution in Britain, where industrial production in large factories transformed working life. At that time, the working day could range from 10 to 16 hours, the work week was typically six days a week and the use of child labour was common. The first country that introduced the 8-hour work day by law for factory and fortification workers was Spain in 1593. In Contemporary Era, it was established for all professions by the Soviet Union in 1917.