The My Lai Massacre (lang-vith?m s�t M? Lai IPA-vim?? l??j; IPA-en?ma??le?, ?ma??la?-My Lai.ogg, IPA-vim??la?jlang) was the mass murder conducted by a unit (Company (military unit)) of the U.S. Army on March 16, 1968 of 347 to 504 unarmed citizens in South Vietnam, all of whom were civilians and a majority of whom were women, children (including babies) and elderly people.

Many of the victims were sexually abused (Sexual abuse), beaten, tortured, and some of the bodies were found mutilated. The massacre (List of events named massacres) took place in the hamlets of M? Lai (My Lai, Vietnam) and My Khe of S?n M? (Son Tinh) village during the Vietnam War. While 26 U.S. soldiers were initially charged with criminal offenses for their actions at My Lai, only William Calley was convicted. He served only three years of an original life sentence, while on house arrest.

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 U.S. servicemen who made an effort to halt the massacre and protect the wounded were denounced by U.S. Congressmen, received hate mail and death threats and found mutilated animals on their doorsteps. Only 30 years after the event were their efforts honored.

The massacre is also known as the S?n M? Massacre (lang-vith?m s�t S?n M?) or sometimes as the Song My Massacre. The U.S. military codeword for the hamlet was Pinkville.