The 12. Armee was formed 18 August  1939 from Arbeitsstab von Rundstedt and was redesignated Heeresgruppe Süd on 2 September 1939.

The 12. Armee was reformed 13 October  1939 by the redesignation of the 14. Armee. The commander of the 12. Armee served also as the Wehrmachtbefehlshaber Südost from June 1941-31 December 1942. It was redesignated Heeresgruppe E on 31 December 1942.

The 12. Armee was again reformed on 10 April 1945 from the staff of Heeresgruppe Nord. During the period 4-8 May 1945, the 12. Armee, along with the remnants of the 9. Armee, crossed to the west bank of the Elbe and surrendered to the U.S. Ninth Army.

Commanders

Generalfeldmarschall Wilhelm List (13 Oct 1939 - 15 Oct 1941)
General der Pionere Walter Kuntze (29 Oct 1941 - 2 July 1942)
Generaloberst Alexander Löhr (2 July 1942 - 31 Dec 1942)
General der Panzertruppen Walther Wenck (10 Apr 1945 - 7 May 1945)

Chiefs of the General Staff

General der Kavallerie Eberhard von Mackensen (13 Oct 1939-1 Jan 1941)
Generalmajor Hans von Greiffenberg (1 Jan 1941-10 May 1941)
Generalmajor Hermann Foertsch (10 May 1941-31 Dec 1942)
Oberst Günther Reichhelm (10 Apr 1945-7 May 1945)

Operations Officers (Ia)

Oberst Otto Wöhler (13 Oct 1939-15 Oct 1939)
Oberst Josef Kübler (15 Oct 1939-Jun 1941)
Unknown (Jun 1941-10 Nov 1941)
Oberstleutnant Robert Macher (10 Nov 1941-15 Jul 1942)
Oberst Hans-Joachim Schipp von Branitz (15 Jul 1942-31 Dec 1942)
Oberstleutnant Hubertus Freiherr von Humboldt-Dachroeden (10 Apr 1945-7 May 1945)

Holders of high awards

Holders of the German Cross in Silver (1)
- Haack, Hermann, 23.02.1943, Generalstabsintendant, Armee-Intendant AOK 12
Holders of the Knight's Cross (1)
- Greiffenberg von, Hans 18.05.1941 Generalmajor Chef d. Gen.St. 12. Armee

Order of battle (27 June 1941)

At the disposal of the 12. Armee
- 164. Infanterie-Division + Infanterie-Regiment 125
XVIII. Gebirgs-Armeekorps
- 5. Gebirgs-Division
- 6. Gebirgs-Division
Höheres Kommando z.b.V. LXV
- 717. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 718. Infanterie-Division

Order of battle (3 Sep 1941)

XVIII. Gebirgs-Armeekorps
- 5. Gebirgs-Division
- 713. Infanterie-Division
- 164. Infanterie-Division + Infanterie-Regiment 125
Höheres Kommando z.b.V. LXV
- 717. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 718. Infanterie-Division

Order of battle (2 Jan 1942)

Festungs-Division Kreta undergoing formation with:
- Infanterie-Regiment 125
- 713. Infanterie-Division
- 164. Infanterie-Division
Höheres Kommando z.b.V. LXV (Bevollmächtigter Kommandierender General in Serbien)
- 718. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 717. Infanterie-Division
- 342. Infanterie-Division
- 113. Infanterie-Division (in transit)

Order of battle (11 May 1942)

At the disposal of the 12. Armee
- Infanterie-Regiment 440
Festungs-Division Kreta
Kommandierender General und Befehlshaber in Serbien
- 718. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 717. Infanterie-Division

Order of battle (12 Aug 1942)

At the disposal of the 12. Armee
- Infanterie-Regiment 440
- 22. Infanterie-Division (in transit)
Festungs-Division Kreta
Kommandierender General und Befehlshaber in Serbien
- 718. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 717. Infanterie-Division

Order of battle (12 Nov 1942, 22 Dec 1942)

At the disposal of the 12. Armee
- Infanterie-Regiment 440 (LL)
Festungs-Brigade Kreta
- 22. Infanterie-Division (in transit)
Kommandierender General und Befehlshaber in Serbien
- 718. Infanterie-Division
- 714. Infanterie-Division
- 704. Infanterie-Division
- 717. Infanterie-Division
- SS-Freiwilligen-Gebirgs-Division “Prinz Eugen”

Order of battle (30 Apr 1945)

At the disposal of the 12. Armee
- Stab 349. Feldausbildungs-Division
- 199. Infanterie-Division
Korps Reimann
- Infanterie-Division “Friedrich Ludwig Jahn” (RAD Nr. 2)
- 18. Panzer-Grenadier-Division
XXXXI. Panzerkorps
- Division “von Hake”
- Division “Gaudecker”
- Division z.V.
XXXIX. Panzerkorps
- Infanterie-Division “Berlin”
- Division “Mayer”
- 84. Infanterie-Division
XX. Armeekorps
- Infanterie-Division “Theodor Körner” (RAD Nr. 3)
- Infanterie-Division “Scharnhorst”
- Infanterie-Division “Ulrich von Hutten”
- Division “von Schill”
XXXXVIII. Panzerkorps
- Division “Raegener”
- Division “Sachsen”

Notable members

Rudolf-Christoph Freiherr von Gersdorff (Active in the resistance against Hitler and also the one who in 1943 discovered the mass graves from the Soviet massacre of Polish officers in the Katyn forest)
Alexander Löhr (Generalmajor in the Austrian Bundesheer before the Anschluss. He was executed for war crimes in Yugoslavia 1947)

SS-Obergruppenführer Joseph Dietrich, Generalmajor Hans von Greiffenberg and Generalfeldmarschall Wilhelm List during the surrender negotiations in Greece April 1941

(Courtesy of Bundesarchiv/Wikimedia, licensed under Creative Commons Attribution ShareAlike 3.0 Germany)

Sources used

Research by Shawn Bohannon
Georg Tessin - Verbände und Truppen der deutschen Wehrmacht 1933-1945

Reference material on this unit

Alex Buchner - Der deutsche Griechenland-Feldzug: Operationen der 12. Armee 1941
Franz Kurowski - Armee Wenck: Die 12. Armee zwischen Elbe und Oder 1945