Gules, a chevron Azure fimbriated Or between three fleurs-de-lis and a lamb couchant of the third.
That for the regiments and separate battalions of the Illinois Army National Guard: On a wreath of the colors Or and Gules upon a grassy field the blockhouse of old Fort Dearborn, Proper.
PARATI ET VOLENTES (Ready And Willing).
The shield is red for Artillery. The blue chevron alludes to the Infantry origin and the ability with which the regiment always obtained its objective. The three fleurs-de-lis symbolize the three major engagements in which the 123d Field Artillery participated during World War I Lucey Sector (Lorraine), St. Mihiel Offensive, and Meuse-Argonne Offensive. The lamb is taken from the seal of Puerto Rico and signifies service in Puerto Rico during the Spanish-American War.
The crest is that of the Illinois Army National Guard.
The coat of arms was originally approved for the 123d Field Artillery Regiment, Illinois National Guard on 31 March 1928. It was redesignated for the 123d Field Artillery Battalion, Illinois National Guard on 10 December 1942. The insignia was redesignated for the 123d Artillery Regiment, Illinois National Guard on 19 December 1960. It was redesignated for the 123d Field Artillery Regiment, Illinois Army National Guard on 11 July 1972.