The Merkava Mk.3D is the third and last subvariant of the Merkava Mk.3, which is the third variant of the Merkava main battle tank family. The tank, also known as the Merkava 3 Dor-Dalet (Hebrew for "Fourth Generation"), was enhanced by adding fourth-generation modular composite armour to the turret sides. These sloped modules also function as spaced armour, providing greater protection in urban settings. The Dor-Dalet modular composite armour is extremely similar to the Merkava Mk.4 variant and provides significantly more protection than the preceding Merkava Mk.3s. The tracks were additionally strengthened with a new version supplied by CAT. The Merkava Mk.3D was first used by the Israeli Defense Forces (IDF) in 2000.

Introduced in Update "Raining Fire" as a reward for the 2020 Wargame "Strategist" event, the Merkava Mk.3D is the Merkava Mk.3's last subvariant, with superior modular composite armour. This greatly enhanced the Merkava Mk.3D's turret protection, putting it on par with the Merkava Mk.4 variant. The Merkava Mk.3D, as the final and ultimate subvariant of the Merkava Mk.3, has exceptional post-penetration survivability. Since the crew members are spaced out and no ammunition is stored in the turret, it is difficult to destroy the Merkava Mk.3D in a single shot, especially in hull-down situations. Surviving against anti-tank guided missiles (ATGMs) is also significantly easier, thanks to the modular composite armour's unusual design, which allows it to act as both spaced and composite armour at the same time.