Some German forces committed atrocities against both soldiers and civilians during the Battle of the Bulge that violated international rules governing conduct in war.

On December 17 near the town of Malmedy, Belgium, the 1st SS Panzer Division (Leibstandarte Adolf Hitler), a part of 6th Panzer Army, captured a convoy of American vehicles. The prisoners were marched into an open field, lined up and machine-gunned. At least 75 Americans died; a handful escaped by pretending to be dead, lying for hours in the snow and freezing temperatures. At times other German units fired into the bodies while passing by. The "Malmedy Massacre" became one of the most infamous war crimes committed against American troops in the European Theater.

Nearby, another slaughter of prisoners after they surrendered occurred near the town of Werth, Belgium, but it remained largely unknown for half a century. The 333rd Field Artillery Battalion, an African-American unit in the then-segregated U.S. Army, had used their 155mm guns to delay the German advance on December 16. The following day they were overrun, and groups of men escaped as best they could. Eleven men found their way to home of Mathias Langer, the mayor of Werth. He and his wife, Maria risked their family’s lives to provide shelter to the Americans, but when German troops arrived, the men surrendered to protect their benefactors. The prisoners were marched out of sight before being killed, and their bodies remained hidden until after the snow had melted. In the confusion of the Bulge, the story of the Werth 11 was lost until the 1990s.

In addition to killing military prisoners of war, many civilians were executed by the Germans, and others died during the fighting in their towns and villages. By some accounts, more Belgian civilians died during the Battle of the Bulge than in the previous four years. Over 115 bodies were found in the towns of Ster and Parfondruy alone. Most war crimes against civilians reportedly occurred in the northern sector of the German attack.