On a shield shaped embroidered item edged with a 1/8 inch (.32 cm) yellow border, blazoned as follows: Per bend sinister Azure and Gules, a knight in armor, holding a lance fesswise, mounted upon a horse all to sinister Or. Attached above the shield, a Blue scroll edged with a 1/8 inch (.32 cm) Yellow border inscribed "KNIGHTS" in yellow. The overall dimensions are 3 1/4 inches (8.26 cm) in height by 2 3/4 inches (6.99 cm) width.

Blue, red and gold are the school colors. Gold suggests generosity; blue denotes steadfastness; scarlet refers to strength of the cadet academic endeavors to military leadership. The knight is the school's mascot, represent vigilance; mounted upon the horse signifies the cadet's journey from citizens to leaders within the school and community.

The shoulder sleeve insignia was authorized 3 August 2018. (TIOH Drawing Number A-10J-1230)

On a shield shaped gold metal and epoxied device 1 1/8 inches (2.86 cm) in width blazoned as follows: Per bend sinister Azure and Gules, in sinister chief a knight's helm affrontée, in dexter base a stylized latte stone, all Argent (Silver Gray). Attached below the shield, a blue scroll inscribed "SOUTHERN HIGH SCHOOL" in gold.

Blue, red and gold are the school colors. The knight helmet suggests the school's mascot, representing vigilance and the cadet's journey from academic endeavors to military leadership, ultimately becoming better citizens and leaders within the school and community. The stylized latte stone is a symbolic of the location of Southern High School in Jose Rita, Guam.

The shoulder loop insignia was authorized 3 August 2018.