The Army Group Mackensen (German language, German: ''Heeresgruppe Mackensen'') which operated in Serbia between 18 September 1915 and 11 October 1916 during World War I under the command of Generalfeldmarschall, field marshal August von Mackensen, Mackensen, was an Army Group of the German Army (German Empire), German Army.
It was renamed on 11 October 1916 to Army Group Below and on 23 April 1917 to Army Group Scholtz, according to its new commander.

1915–1916

This Army Group was established in September 1915 to Serbian campaign of World War I, invade Serbia. The invasion began on 7 October 1915 and by the end of January 1916, the whole of Serbia, Montenegro and the largest part of Albania were in the hands of the Central powers. After that, the Salonika front, front stabilized on the Greek - Macedonian Border.

Composition October 1915

* 11th Army (German Empire), Eleventh Army (Max von Gallwitz) * First Army (Bulgaria), First Army (Kliment Boyadzhiev) * 3rd Army (Austria-Hungary), Third Army (Hermann Kövess von Kövessháza) The Bulgarian Second Army (Bulgaria), Second Army under (Georgi Todorov (general), Georgi Todorov), also participated in the invasion, but remained under the direct control of the Bulgarian high command.

1916–1918

On 30 July 1916, Field Marshal Mackensen left for the Romania during World War I, Romanian Front and the Army Group was temporarily commanded by the Bulgarian High Command. On 11 October 1916, Otto von Below became the new commander and the Army Group was renamed Army Group Below (German language, German: ''Heeresgruppe Below'').
On 23 April 1917, von Below was replaced by Friedrich von Scholtz, and the Army Group was again renamed Army Group Scholtz (German language, German: ''Heeresgruppe Scholtz'').

Composition 1916 - 1918

* German 11th Army (German Empire), Eleventh Army (Arnold von Winckler, succeeded by Kuno von Steuben) * Bulgarian First Army (Bulgaria), First Army (Kliment Boyadzhiev, succeeded by Dimitar Geshov)

Sources

*
Die Deutschen Heeresgruppen im Ersten Weltkrieg
{{no footnotes, date=December 2015 Army groups of the Imperial German Army, Mackensen Military units and formations of Germany in World War I Military units and formations established in 1916 Military units and formations disestablished in 1918