Only a few months after the Tiger I tank was put into full production, the German High Command submitted a new requirement for a follow-on heavy tank design that was to incorporate thick sloped armor and an even more powerful 88mm gun. The vehicle that emerged from the competition, again between the firms of Henschel and Porsche, was the Panzerkampfwagen VI Ausf. B "King Tiger" tank (SdKfz 182): generally assessed to be the most powerful - not to mention largest and heaviest - tank to see combat during World War II.

As with the competition for the Tiger I, Henschel's design won the bid for the King Tiger. The layout of the new King Tiger tank was typical of other WW II German tanks: the engine - a Maybach HL 230 P 30 12-cylinder producing 700hp - was mounted in the rear, and provided power to the front drive sprockets by means of a driveshaft that passed under the fighting compartment to the transmission in the front of the hull. The five crewmembers occupied traditional positions: the driver in the hull front on the left; the radio operator/hull machine gunner in the hull front on the right, with the transmission in between; the gunner in the turret to the left of the main gun; the commander behind him; and the loader on the right side of the turret.

The King Tiger's running gear was a similar interleaved road wheel design as Henschel had used for the Tiger I, and MAN used for the Panther. The King Tiger's suspension had nine torsion bars per side supporting interleaved steel-rimmed road wheels. As mentioned above, the drive sprockets were at the front of the vehicle, with an idler wheel in the rear and no return rollers. As with the Tiger I tank, the metal tracks were quite wide: almost 2.8m across!

True to the design specification, the vehicle's armor plate was well-sloped and very thick: 185mm on the turret front, 150mm on the hull glacis, and 80mm on the sides and rear. The roof plating was also relatively thick at 40 to 45mm, with armor plate on the bottom of the hull running from 40mm to 25mm thick. This massive amount of armor plate gave the vehicle an incredible amount of protection, but it also led to its greatest drawback: a weight of 68 metric tons, 12 metric tons heavier than the Tiger I tank! This had an obvious effect on the King Tiger's mobility, which was even worse than the Tiger I, and also placed an even greater strain on the engine and drive train components. Had the King Tiger (and Tiger I) used a more powerful engine, their mobility could have been significantly improved. As it was, both vehicles used the same basic engine as the Panther tank, which weighed "only" 45 metric tons: at peak output, the Maybach HL 230 engine's 700hp gave the Panther a power to weight ratio of about 15 hp/mt, while the King Tiger's ratio was only a bit over 10 hp/mt. As it was, the King Tiger had a top speed of about 41 km/hr on roads, but only 17 km/hr cross-country. And, needless to say, if the Germans had a hard time finding bridges that would support the Tiger I, they had an even harder time finding ones that would hold the King Tiger!

In another odd turn of the design relationship between Henschel and Porsche, the first fifty production King Tiger tanks, which began rolling off the assembly lines in early 1944, were fitted with turrets designed by Porsche and produced by Wegmann. These turrets featured a rounded front and shaped sides (particularly on the commander's side) that were difficult to produce and had a nasty frontal shot-trap. These turrets were replaced in the production run by a much improved design by Krupp, which employed plates that did not require casting or major machining: they were much easier to make, provided better protection, and also provided additional main gun ammunition stowage, from 72 rounds in hull numbers 1 through 50, to 84 rounds in the vehicles equipped with Krupp turrets. A total of only 485 King Tigers were built.

In the end, despite their strengths and fearsome reputation, the King Tiger tank was yet another attempt by the Third Reich to fend off the inevitable tide of its own destruction. Ironically, the King Tiger drew resources away from other weapons - particularly the Panther tank - that could have made a more significant impact on the German war effort.