The 3rd Army was a field army of the Romanian Land Forces active from the 19th century to the 1990s. It fought as part of the German Army Group B during World War II, in Ukraine, the Crimea, and the Caucasus. General Petre Dumitrescu commanded the 3rd Army for much of that time.

Operation Uranus was the codename of the Soviet Red Army's 19–23 November 1942 strategic operation on the Eastern Front of World War II which led to the encirclement of Axis forces in the vicinity of Stalingrad: the German Sixth Army, the Third and Fourth Romanian armies, and portions of the German Fourth Panzer Army. The Red Army carried out the operation at roughly the midpoint of the five-month long Battle of Stalingrad, aiming to destroy German forces in and around Stalingrad. Planning for Operation Uranus had commenced in September 1942, and developed simultaneously with plans to envelop and destroy German Army Group Center and German forces in the Caucasus.