A gold color metal and enamel device 1 1/16 inches (2.70 cm) in height consisting of a shield blazoned: Azure, three bendlets sinister Argent, a bend double-cottized potente counter-potente Or; on a canton Gules a mullet within a fish-hook fesswise, ring to dexter and barb to base, of the second (for the 5th Field Artillery).
The shield is the shoulder patch of the 3rd Division, the bend and bendlets are from the arms of Champagne. The canton indicates the parentage of the regiment. The fishhook and Star are from the coat of arms of the 5th Field Artillery; the union battle line of Gettysburg was in the shape of a fishhook and the corps badge of Slocum's 12th Corps was a star.
The distinctive unit insignia was originally approved for the 18th Field Artillery Regiment on 2 October 1923. It was amended to correct the method of wear on 25 May 1925. It was amended to correct the blazon on 12 July 1928. It was redesignated for the 18th Field Artillery Battalion on 4 September 1943. The insignia was redesignated for the 18th Artillery Regiment on 18 November 1958. It was again redesignated for the 18th Field Artillery Regiment effective 1 September 1971.