I18

I18 may refer to:


 * HMCS Assiniboine (I18), a 1939 River-class destroyer that served in the Royal Canadian Navy
 * HMS Kempenfelt (I18), a 1931 C-class destroyer of the Royal Navy
 * JAPANESE SUBMARINE I-18, a 1939 Type C submarine of the Imperial Japanese Navy
 * Västmanland Regiment (1816–1927), a Swedish Army infantry regiment
 * Gotland Infantry Regiment (1928–1963), a Swedish Army infantry regiment