A12 can be:

• The A12 road in England.

• One of three separate aircraft:
  • The A-12 Shrike, a World War II-era aircraft
  • The A-12 OXCART, a CIA reconnaissance aircraft that formed the basis of the SR-71 Blackbird
  • The A-12 Avenger II, a Cold War-era aircraft project that was cancelled prior to production.

• The A12 rocket, designed during the Second World War.