A gold color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a vertical gold arrow with red arrowhead and red flight feathers extended between a saltirewise upper part of a gold Nike missile issuing from base and a gold antiaircraft shell, charged overall in the center with a fleur-de-lis, all in front of and extending over a gold octagon bearing throughout a celestial blue nebuly disc; and encircling the sides and base of the octagon a red scroll terminating at the heads of the missile and shell respectively and borne in back of the arrow shaft in base inscribed "DEFENSE" on one side and "IN DEPTH" on the other in gold letters.
Scarlet and gold (yellow) are the colors used for Air Defense Artillery. The organization's campaign awards for service in the European Theater, World War II, are commemorated by the scarlet fleur-de-lis. The scarlet arrowhead denotes the award for the assault landing, Normandy. The Group's historic Antiaircraft Artillery service is depicted by the shell. The subsequent participation in the early operations of the Nike missile program is indicated by the missile. The nebuly celestial blue disc connotes the Air Defense mission of the unit. The upright arrow and octagon additionally allude to the numerical designation of the Group.
The distinctive unit insignia was originally approved for the 18th Artillery Group on 5 June 1969. It was redesignated for the 18th Air Defense Artillery Group on 4 April 1972.