The French 18th Army Corps () was a French military unit created in November 1870 by vice admiral Fourichon.
The 18th Army Corps was formally organised by the decrees of 28 September 1873 and 2 August 1874, issued under the presidency of the French Third Republic to complete the post-war reorganisation of the army into eighteen metropolitan corps and one in Algeria.
During the Battle of France in 1940, the 18th Army Corps was commanded by Général de corps d'armée Eugene Jules Rochard (succeeded by Paul-André Doyen). The corps headquarters was located at Dun-sur-Meuse.