Mass graves in Celje were created in Celje, Slovenia, after the Second World War, from 1945 to 1956. The 11 known mass graves in Celje itself and 14 in the immediate vicinity include some of the largest mass graves in Slovenia.

Celje is the fourth-largest city in Slovenia. It is a regional center of the traditional Slovenian region of Styria and the administrative seat of the City Municipality of Celje. The town of Celje is located below Upper Celje Castle at the confluence of the Savinja, Hudinja, Ložnica, and Voglajna rivers in the lower Savinja Valley, and at the crossing of the roads connecting Ljubljana, Maribor, Velenje, and the Central Sava Valley. It lies 238 m (781 ft) above mean sea level (MSL).