Grey aliens, also referred to as Zeta Reticulans, Roswell Greys, Greys, or Grays, are purported extraterrestrial beings whose existence is discussed in ufological, paranormal, and New Age communities and who are named for their unique skin color. Forty-three percent of all reported alien encounters in the United States describe Grey aliens.


Such claims vary in every respect, including the nature, origins (e.g. extraterrestrials, extradimensionals, time travelers, or machines), moral dispositions, intentions, and physical appearances of the encountered beings, though many of them nonetheless share some noticeable similarities. A composite description derived from this overlap would have Greys as small-bodied beings with smooth grey-colored skin, enlarged hairless heads and large black eyes.


The popularization of the idea of the Grey alien is commonly associated with the Barney and Betty Hill abduction claim, which purportedly took place in New Hampshire in 1961, although skeptics see precursors in science fiction and earlier paranormal claims; Grey aliens are also famed from earlier depictions of the 1947 Roswell UFO incident.


Some sources in the UFO community describe the Grey aliens as artificially created/modified race used by other alien races as servants or even slaves to execute tasks such as abductions and others. Whatever the origin, the Grey alien has since emerged as an archetypal image of sentient non-human creatures and extraterrestrial life in general, as well as an iconic trope of popular culture in the age of space exploration.