Luis Elizondo is an American author, media personality and UFO disclosure activist formerly employed by the United States Department of Defense.

Elizondo claims that some UFOs are of extraterrestrial, cryptid, or "interdimensional" origin, and that the US Government is withholding and suppressing this information. He has been criticized for not offering physical evidence for his assertions, and for presenting images of mundane objects, such as light fixtures and irrigation circles, as possible alien spaceships.

Elizondo is the son of Luis Elizondo III, a Cuban exile who volunteered for Brigade 2506, a CIA-sponsored group of exiles formed in 1960 to attempt the military overthrow of the Cuban government headed by Fidel Castro, which culminated in the Bay of Pigs invasion. According to his 2024 memoir, Elizondo grew up being trained for Alpha 66, which he describes as a "slightly rebranded Brigade 2506".

Elizondo was born in Texas. Elizondo graduated from Riverview High School in Sarasota, Florida. At the University of Miami, Elizondo studied microbiology and immunology.

Elizondo enlisted in 1995 and served in the United States Army with service in the Republic of Korea, Kuwait, and in the United States, and then as a civilian intelligence officer during which he ran military intelligence operations in Afghanistan, South America, and the Guantanamo Bay detention camp and its Camp Seven. Elizondo ran anti-terrorist missions against the Islamic State (ISIS), al-Qaeda and the Lebanese militant group Hezbollah.

Starting in 2008, Elizondo worked with the Office of the Under Secretary of Defense for Intelligence (OUSDI) in the Pentagon. Elizondo has reported that he worked with officials from the U.S. Navy and the CIA out of his Pentagon office for this program until 2017.

Elizondo was allegedly recruited in 2009 to the Advanced Aerospace Threat Identification Program (AATIP), a government program to investigate aerial threats including unidentified aerial phenomena. At AATIP, Elizondo was reputedly tasked with investigating "the national-security implications of military U.A.P. encounters". Elizondo told a reporter he thought that he might have been selected for AATIP because of his scientific background, work as a counterintelligence agent protecting American aerospace technology, and lack of interest in science fiction. Writer Keith Kloor reported in 2019 that Elizondo was asked to take over management of security for AATIP, describing Elizondo as among a group of "believers in extraterrestrial visitations", and that performance evaluations of Elizondo's work as a government employee were favorable. According to the Department of Defense, the AATIP program ended in 2012 due to budget cuts. However, Elizondo's role within the AATIP has been questioned, including by Keith Kloor who originally supported his claims, and there is a lack of confirming evidence that he was involved in the program.

Government spokespeople have issued alternating and conflicting accounts of his role in government, both confirming and denying his intelligence work related to the topics of unidentified flying objects (UFOs) and unidentified anomalous phenomenon (UAPs). Elizondo has been called a "leader" with responsibility for management of security for AATIP. In 2017, Elizondo was confirmed as an AATIP leader by Pentagon spokeswoman Dana White to Politico. In June 2019, Pentagon spokesperson Christopher Sherwood confirmed that AATIP "did pursue research and investigation into unidentified aerial phenomena", and added to The Intercept that Elizondo "had no responsibilities with regard to the AATIP program while he worked in OUSDI, up until the time he resigned". Senator Harry Reid sent a letter in 2021 to NBC News stating, "As one of the original sponsors of AATIP, I can state as a matter of record Lue Elizondo’s involvement and leadership role in this program". Garry Reid, who served as director of Defense Intelligence at the USDI office, stated in a memo that Elizondo “aggrandized his role” and that “to the best of my knowledge, [Elizondo] had no job responsibilities related to the AATIP.”