The 40-hour week movement, or eight-hour day movement, was a social movement to regulate the length of a working day.

40-hour week may also refer to:

• Forty-Hour Week Convention, 1935, International Labour Organization Convention
• Labour law, including regulation of working time
• Working time, the period of time that a person spends at paid labor
• Workweek and weekend#Length

• 40-Hour Week, an album by Alabama
  • "40 Hour Week (For a Livin')", the title song