4040, 40-40 or 40/40 may refer to:

• The year 4040 in the 5th millennium

• Intel 4040, a microprocessor
• Commodore 4040, a model of floppy disk drive

• County Road 4040 (Volusia County, Florida), a historic road
• A4040 road, a road in Birmingham, England

• 40–40 club, a term in baseball
• The 40/40 Club, a sports bar chain
• Forty forty, a children's game

• 40/40 (The Carpenters album)
• 40/40: The Best Selection (Olivia Newton-John album)

• 4040 Purcell, an asteroid