The Abydos helicopter (a.k.a. Abydos Submarine, Abydos Jet Plane, Abydos UFO, etc.) is a pseudoscientific modern myth that has been spread rapidly via the Internet concerning the singular appearance of a re-carved inscription in the mortuary temple of Seti I in Abydos, Egypt. It is claimed this carving depicts various high-tech or alien technologies, such as submarines, jet planes, and UFOs, thus playing into the theories that Ancient Egyptian civilization was either influenced or founded by aliens or Atlanteans.

It is also claimed that the inscription in question depicts various advanced technologies, such as jet aircraft, UFOs, helicopters, and even submarines, although no effort is ever made to explain the practical use the latter would have in the Nile, the most important waterway to the Egyptians, notable more for its shallow depth and sandbanks than its abyssal depths and submarine warfare raging beneath the papyrus skiffs of the commoners.

The existence of these inscriptions is used to "prove" such technology was known to ancient civilizations, which is then often used as "proof" for alien or Atlantean involvement in the early development of ancient civilizations. Egyptologists dismiss such claims, and regard the Abydos inscription as a simple case of a filled and re-carved titulary, something which is commonly seen in Egyptian temples.