Karl Wolfe, whose name is also spelled Karl Wolf, was a former U.S. Air Force sergeant who became widely known in 2001 for saying he had seen photographs of artificial structures on the Moon, an account he gave to Steven Greer for the Disclosure Project. Recorded in September 2000 and published in Greer's 2001 book of witness testimony, the interview kept circulating long after Wolfe's passing in 2018.

Wolfe said he served from January 18, 1964, to October 18, 1968, leaving a few months early to return to school. By his account he held a top-secret crypto clearance and worked as a photographic technician with an electronics background in the 4444th Reconnaissance Technical Group, part of Tactical Air Command at Langley Air Force Base in Virginia. He described the unit as processing reconnaissance film from U-2 flights, satellites and combat aircraft.

His testimony centers on a repair call he dated to about June or July of 1965. Wolfe said his supervisor sent him to fix computerized contact-printing equipment at a facility on the base that was receiving images from the first Lunar Orbiter mission, a site his boss called an NSA facility. There, he said, an airman of the same rank told him "we've discovered a base on the backside of the moon" and showed him a photo mosaic with tall towers, spherical and domed buildings and a structure shaped like a radar dish. Comparing it with photographs he collected later, Wolfe estimated some structures at half a mile across. He said he looked only briefly, never obtained copies and kept silent for decades out of respect for his clearance.

The published mission record does not match his timing. NASA, whose Langley Research Center managed the Lunar Orbiter program, lists the first spacecraft's launch as August 10, 1966, about a year after the period Wolfe gave, and describes its main task as photographing smooth areas of the lunar surface to choose landing sites for the Surveyor and Apollo missions.

Wolfe passed away in 2018, at 74, in Lansing, New York; Fox News's report on his passing recalled his claims that NASA had hidden evidence of lunar structures. His interview drew new audiences in 2026. In June a video essay posted to several Reddit forums paired his lunar account with remote-viewing and secret-space-program claims, and in July researcher Joe Murgia reposted the interview, arguing that disclosure of ancient structures on Mars or the Moon would come before disclosure about UFOs and calling Wolfe credible in his view. A quarter-century after it was recorded, his interview is still shared as military testimony for the claim of a hidden base on the Moon's far side.