The T-90A is the first variant of the T-90 main battle tank family. Intended to replace the T-72 main battle tank family as the new armoured spearhead, it features many improvements, such as a new 125 mm 2A46 tank gun, the 1A45T fire-control system, an upgraded engine, and advanced gunner's sight with thermal imaging equipment. Standard protection measures include steel and composite armour, smoke grenade dischargers, Kontakt-5 explosive reactive armour (ERA), and the Shtora-1 infrared anti-tank guided missile (ATGM) jamming system. When a weapon-guidance laser is directed at the tank, the jamming system first warns and highlights the direction for the tank's crew. After the crew has directed the turret to face the threat, the infrared jammer, TShU1-7 EOCMDAS, jams the semi-automatic command to line of sight (SACLOS) guidance system used by some anti-tank guided missiles (ATGM) to neutralize the threat.

Introduced in Update "New Power", the T-90A has a playstyle that is similar to that of traditional Soviet main battle tanks. It excels in support roles as well as flanking and sniping, thanks to its low profile and strong frontal armour. Due to its slow reverse speed, which is an inherent flaw in almost all Soviet main battle tanks, close-range engagements are not recommended unless absolutely necessary. It is best to take a hull-down position early in the game and lay down supportive fire for friendly forces leading the assault.