003

003, O03, 0O3, OO3 may refer to:

• 003, former emergency telephone number for the Norwegian ambulance service (until 1986)
• 1990 OO3, the asteroid 6131 Towen
• OO3 gauge model railway
• O03 (O2) and other related blood type alleles in the ABO blood group system and ABO
• O03 Morganville Airport, see list of airports in Pennsylvania
• Tyrrell 003, 1971 Formula One season car
• BAR 003, 2001 Formula One season car
• 003 (album), by Đorđe Balašević
• BMW 003 turbojet engine
• 003 (UN M.49 code) for North America
• Type 003 aircraft carrier of China
• Scuderia Cameron Glickenhaus SCG 003, an American supercar