Armee) was a World War II field army in the German Wehrmacht.

Formed in November 1939 in Military Region (Wehrkreis) VI, the 18th Army was part of the offensive into the Netherlands (Battle of the Netherlands) and Belgium (Battle of Belgium) during Fall Gelb and later moved into France in 1940.

The 18th Army was then moved East and participated in Operation Barbarossa in 1941.

In October 1944, the army was encircled by the Red Army offensives and spent the remainder of the war in the Courland Pocket.

On 22 July 1940, the 18th Army consisted of XXVI Corps (161st and 271st Infantry Divisions), XXX Corps (76th and 258th Infantry Divisions), Higher Command XXXV (162nd and 292nd Infantry Divisions), III Corps (62nd and 75th Infantry Divisions), XVII Corps (297th and 298th Infantry Divisions) and Higher Command XXXIV (68th and 257th Infantry Divisions), as well as XXXXIV Corps and 291st Infantry Division as reserves and limited authority extended to Panzer Group Guderian with XXXX Corps and XVI Corps.