Reserve-Korps / XXXVIII RK) was a corps level command of the German Army in World War I. XXXVIII Reserve Corps was formed in December 1914.

The personnel was predominantly made up of kriegsfreiwillige (wartime volunteers) who did not wait to be called up.

[4] The Corps was still in existence at the end of the war[5] in the 3rd Army, Heeresgruppe Deutscher Kronprinz on the Western Front.

[6] On formation in December 1914, XXXVIII Reserve Corps consisted of two divisions.

[7] but was weaker than an Active Corps In summary, XXXVIII Reserve Corps mobilised with 18 infantry battalions, 2 cavalry detachments, 24 field artillery batteries (96 guns), 2 cyclist companies and 2 pioneer companies.