Shield
Per fess embattled Sable and Gules masoned Argent (Silver Gray), in base an ace of the first, fimbriated of the third; perched upon the embattled wall a griffin passant Or, holding in dexter paw a lightning bolt bend sinisterwise Tenn and a key palewise, wards upward and to dexter Celeste (Oriental Blue), within a demi-orle of five segments Celeste (Light Blue), of the fifth, of the sixth, of the second and of the fourth.
Crest
That for the regiments and separate battalions of the Texas Army National Guard: From a wreath Or and Sable a mullet Argent encircled by a garland of live oak and olive Proper.
Motto
PUGNA PROUT UNUS (Fight As One).
Shield
The castle wall represents the Engineering unit that provides the foundation of the original unit of the Special Troops Battalion and also represents the current Engineer Battalion. The griffin alludes to the tactical strength and defense capability of the unit provided by the Military Police element. The lightning bolt symbolizes the command and control elements of the Signal asset. The key signifies the knowledge that the Military Intelligence assets provided to the Brigade by the Battalion. The ace is a good luck symbol for the newly formed unit. It also provides continuity for the unit as a connection to how the ace was used by Soldiers in previous conflicts and wars. The five colors are for the five assets that make up the Special Troops Battalion: light blue is the color associated with Infantry, orange is for the Signal Corps, oriental blue is for the Military Intelligence, red represents the Engineers and yellow is for the Military Police.
Crest
The crest is that of the Texas Army National Guard.
The coat of arms was originally approved for the Special Troops Battalion, 72d Brigade Combat Team, 36th Infantry Division on 21 April 2010. It was redesignated for the 172d Engineer Battalion with the blazon and symbolism updated effective 1 September 2016.