A gold color metal and enamel device 1 3/16 inches (3.02 cm) in height overall consisting of a gold demi-Philippine sunburst bearing a blue fleur-de-lis issuing from a scarlet masoned tower with three merlons above a blue area surmounted by a vertical white arrowhead, with point extending up on the tower; in base an open wreath of gold pine cones with needles, all above a semi-circular gold scroll folded into three sections, terminating at each side of the tower and inscribed DEVELOP, DESIGN, DIRECT in blue letters.
The Philippine sunburst symbolizes the units participation in four campaigns in the Pacific Theater, World War II, and the award of the Philippine Presidential Unit Citation, the arrowhead on the blue background referring to the units assault landing on Luzon. The fleur-de-lis represents the Groups six campaigns in France during World War I. The blue area and the pine branches also refer to the units headquarters at Waterville, Maine, on the banks of the Kennebec River. The masoned tower alludes to the former organizations mission to perform engineer planning and design functions required in support of field construction. Scarlet and white are colors used by the Corps of Engineers and reflect the original unit designation.
The distinctive unit insignia was originally approved for the 240th Engineer Group on 23 December 1971. It was redesignated for the 120th Support Group with the description and symbolism updated effective 1 September 2008.