4040, 40-40 or 40/40 may refer to:
- The year 4040 in the 5th millennium
Computers
- Intel 4040, a microprocessor
- Commodore 4040, a model of floppy disk drive
Roads
- County Road 4040 (Volusia County, Florida), a historic road
- A4040 road, a road in Birmingham, England
Sports and games
- 40–40 club, a term in baseball
- The 40/40 Club, a sports bar chain
- Forty forty, a children's game
Music
- 40/40 (The Carpenters album)
- 40/40: The Best Selection (Olivia Newton-John album)
Other
- 4040 Purcell, an asteroid