XVIII. Armeekorps was formed in Salzburg, Austria, on 1 April 1938, following the Anschluss of Austria into the German Reich. During the life of the XVIII. Armeekorps, they took part in the Polish campaign, Fall Weiss, and performed occupation duties in France. On the 30th of October, 1940, they absorbed elements of the XXXXIX. Armeekorps, and on the following day, the 1st of November, they re-designated the Korps name to XVIII. Gebirgskorps.