Gules, on a bend Azure fimbriated Argent the badge of the Essex Regiment Or; on a canton of the third a cross of the first.
That for the regiments of the Massachusetts National Guard: On a wreath of the colors Argent and Gules a dexter arm embowed clothed blue and ruffed White Proper the hand grasping a broad sword Argent the pommel and hilt Or.
TENAX PROPOSITI (Tenacious of Purpose)
The shield is red for the Engineer Corps. The blue bend denotes service as Infantry. The badge is that formerly used by the Essex Regiment, while the canton the colonial origin of the regiment.
The crest is that of the Massachusetts National Guard.
The coat of arms was originally approved for the 101st Regiment Engineers on 3 Nov 1938. It was redesignated for the 101st Engineer Battalion on 1 Aug 1942.