The Marzabotto massacre (), also known in recent historiography as the Monte Sole massacre ( or ), was a World War II massacre of Italian civilians committed by German forces between 29 September and 5 October 1944 in the Monte Sole area, south of Bologna, Italy. The killings took place in scattered villages, farmsteads, churches, cemeteries and shelters in the municipalities of Marzabotto, Monzuno and Grizzana Morandi, between the Reno and Setta valleys.
The massacre is commonly known internationally as the Marzabotto massacre because many of the affected localities belonged to the municipality of Marzabotto. Historians and local institutions often use the name Monte Sole massacre, which more accurately identifies the wider mountainous area in which the killings occurred.
Modern scholarship generally interprets the killings as part of a planned anti-partisan and annihilation operation, rather than as a spontaneous or limited reprisal. The operation was directed against the area in which the Brigata Stella Rossa partisan formation operated, but most of those killed were civilians with no direct role in armed combat.
The massacre was not confined to a single village. It consisted of a series of interconnected killings in 115 different places, including hamlets, farmhouses, churches, cemeteries and woodland shelters. The operation was accompanied by the burning of houses and the destruction of civilian settlements. The Atlas of Nazi and Fascist Massacres in Italy classifies the episode as an "eliminatory massacre".
Walter Reder was tried before the Military Tribunal of Bologna in 1951. He was convicted for his responsibility in massacres including Monte Sole and sentenced to life imprisonment. The sentence was confirmed in 1954 by the Supreme Military Tribunal. Reder was granted conditional release in 1980 and returned to Austria in 1985.
On 13 January 2007, the Military Tribunal of La Spezia sentenced ten defendants to life imprisonment in absentia and acquitted seven. On 7 May 2008, the Military Court of Appeal in Rome partly modified the first-instance judgment: it confirmed several life sentences, acquitted one defendant for insufficient evidence, declared one case extinguished because of the death of the defendant and sentenced Wilhelm Kusterer, who had been acquitted at first instance, to life imprisonment. None of those convicted was extradited or imprisoned in Italy.