The Mỹ Lai Massacre was the Vietnam War mass killing of between 347 and 504 unarmed civilians in South Vietnam on March 16, 1968. It was committed by U.S. Army soldiers from the Company C of the 1st Battalion, 20th Infantry Regiment, 11th Brigade of the 23rd (Americal) Infantry Division. Victims included men, women, children, and infants. Some of the women were gang-raped and their bodies mutilated. Twenty-six soldiers were charged with criminal offenses, but only Lieutenant William Calley Jr., a platoon leader in C Company, was convicted. Found guilty of killing 22 villagers, he was originally given a life sentence, but served only three and a half years under house arrest.
The incident prompted global outrage when it became public knowledge in November 1969. The My Lai massacre increased to some extent domestic opposition to the U.S. involvement in the Vietnam War when the scope of killing and cover-up attempts were exposed. Initially, three U.S. servicemen who had tried to halt the massacre and rescue the hiding civilians were shunned, and even denounced as traitors by several U.S. Congressmen, including Mendel Rivers, Chairman of the House Armed Services Committee. Only after thirty years were they recognized and decorated, one posthumously, by the U.S. Army for shielding non-combatants from harm in a war zone.