Samuel A. Adams (June 14, 1934 – October 10, 1988) was an analyst for the Central Intelligence Agency who is best known for discovering underestimated Vietcong and North Vietnamese Army troop numbers during the Vietnam War. He eventually retired from the CIA after claiming there was a conspiracy among officials within U.S. Headquarters in Saigon. He died in 1988 of an apparent heart attack.

Family and education
Adams was a member of the Colonial Adams family of Massachusetts. He was a graduate of St. Mark's School in Southborough, Mass., and of Harvard College.

Troop number controversy
Adams was in the CIA from 1963 until 1973, but grew frustrated with the perversion of intelligence to meet political objectives. He claimed U.S. Army General William C. Westmoreland had conspired to minimize Vietnamese enemy troop strength in 1967. In 1982 Adams provided critical evidence to CBS News reporters who made the documentary “The Uncounted Enemy: A Vietnam Deception”. General Westmoreland subsequently sued both Adams and CBS News for libel, but the case was settled privately.
He testified for the defense in the espionage trial of Daniel Ellsberg and Anthony J. Russo, accused in connection with the illegal transmission of the Pentagon papers, a secret Government-sponsored history of the Vietnam War. Citing Government misconduct, a Federal judge dismissed all charges against the two. Mr. Adams told the court in that trial that he believed there had been political pressures in the military to depict the North Vietnamese and Vietcong in 1967 as weaker than they actually were. After visiting South Vietnam four times between 1966 and 1967, Mr. Adams concluded that senior military intelligence officers were underestimating the strength of the enemy, perhaps by half. He argued for a higher troop count, but late in 1967 the C.I.A. reached an agreement with the military on lower figures. Adams responded with an internal memorandum calling the agreement a monument of deceit. In January 1968, after the Tet offensive in Vietnam, the CIA adopted an enemy count along the lines he had recommended. By then, he had left the Vietnamese affairs staff in protest, and was concentrating on Cambodia.
In 1969 Mr. Adams removed CIA documents to argue his case and buried them in the woods near his 250-acre (1.0 km²) farm in Virginia. After his resignation from the agency in 1973, he sought the support of other intelligence officials to prove that there was a Saigon cover-up. From the massive chronologies Mr. Adams compiled, he detailed his allegations in a Harper's Magazine article in 1975. He also testified before the House Select Committee on Intelligence, which reached conclusions similar to his own.
The Sam Adams Award for integrity in intelligence is named after Adams.