The My Lai Massacre was the Vietnam War mass murder of 347??04 unarmed civilians in South Vietnam on March 16, 1968, by United States Army soldiers of 'Charlie' Company of 1st Battalion, 20th Infantry Regiment, 11th Brigade of the Americal Division.

Most of the victims were women, children (including babies), and elderly people. Many were raped, beaten, and tortured, and some of the bodies were later found to be mutilated. While 26 US soldiers were initially charged with criminal offenses for their actions at M廙?Lai, only Second Lieutenant William Calley, a platoon leader in Charlie Company, was convicted. Found guilty of killing 22 villagers, he was originally given a life sentence, but only served three and a half years under house arrest.

The massacre took place in the hamlets of M廙?Lai and My Khe of S??n M廙?village. The event is also known as the S??n M廙?Massacre (Vietnamese: th廕σ s獺t S??n M廙? or sometimes as the Song M廙?Massacre.

When the incident became public knowledge in 1969, it prompted widespread outrage around the world. The massacre also increased domestic opposition to the US involvement in the Vietnam War. Three US servicemen who had tried to halt the massacre and protect the wounded were later denounced by US Congressmen. They received hate mail and death threats and found mutilated animals on their doorsteps. It was 30 years before they were honored for their efforts.