The Third Army was a British Army unit.
The German Third Army was a German field army that fought during World War II.
The Third Army was a combat formation of the Hungarian Army which saw action during World War II.
The Soviet Third Army was an important Soviet Red Army field formation during World War II.
The Turkish Third Army is the country's largest army. In the days of the Soviet Union and the Third Army was stationed on the Caucasus border and its border in Thrace to counter any Warsaw Pact or Soviet attack. When the Warsaw Pact and the Soviet Union broke up the General Staff decided to send 120,000 men of the Third Army to the border with Iraq.
The Romanian Third Army was a field army that fought as part of the German Army Group B during World War II. It along with the Romanian Fourth Army bore the brunt of the Soviet Operation Uranus which saw the German Sixth Army encircled and destroyed during the Battle of Stalingrad.