The Panzer IV had the distinction of being the most widely produced German tank of the war, and the only to be produced throughout the whole duration of the European war. It was designed alongside the Pz III as one of the two standard medium tank designs, but focused on supporting infantry rather than in an anti-tank role. As a result, it was equipped with a high-caliber gun (the 7.5cm KwK L/24) that could fire high explosive rounds. Aside from that, the layout and design was broadly similar to the Pz III, the main visual difference being a turret mounted closer to the rear of the hull (the turret also had an electric traverse rather than manual as in the Pz III). Like the Pz III, the turret ring was large enough to allow a wide variety of armament configurations as the tank gradually assumed a more prominent anti-armor role. Mechanical performance was considered good while armor protection was gradually improved as it was initially deemed to be inadequate. Later in the war, many were fitted with Schürzen side and turret skirts which gave them their characteristic late-war appearance while some others had Zimmerit anti-magnetic mine paste added as well. A small number of Pz IVs were in action during the invasion of Poland, and numbers gradually increased until it composed the bulk of Germany's tank strength with the Pz III by the time of Operation Barbarossa. By 1942, the eventual fitting of a high-velocity 7.5cm KwK 40 gave it a significant boost in firepower, enabling it to remain competitive against almost all Allied tanks that it was to face, including the Sherman and the T-34 until the end of the war and long after the Pz III had been retired from front-line service. The Pz IV was also exported in large numbers to Germany's allies, which included Bulgaria, Croatia, Finland, Italy, Rumania and Hungary, as well as Spain and Turkey. A small number of Pz IVs found their way to Syria and these served well into the post-war era, seeing combat during the 1967 Six-Day War.

Origins of the PzKpfw IV (SdKfz 161) began as early as 1935 under the same specification that called for the Pz III. The initial Ausf A and B were built in small numbers but saw action in the early blitzkrieg campaigns, the latter had a six-speed transmission, thicker armor and a revised cupola. The Ausf C was built in larger quantities and had mostly had modest improvements, while the Ausf D had various armor improvements including extra bolt on plates and a thicker mantlet; even thicker plates were added to the Ausf E in addition to a redesigned cupola. The Ausf F came in two versions, the first of which had extra all-around armor as well as wider tracks, while the Ausf F2 was the first to be fitted with the long-barreled 7.5cm KwK 40 gun giving it vastly improved anti-tank capability as it was capable of defeating all Allied armor in mid-1942. The Ausf G that followed was initially identical to the F but later versions had various design improvements as well as Schürzen skirts to the turret and hull sides. It was followed by the Ausf H, the most widely produced version, with a new transmission and thicker base armor. The final tank variant was the Ausf J, which replaced the electric traverse with a manual one, increased the turret armor, among other modifications. Non-tank variants included the Tauchpanzer IV submersible tank, Pz Bef Wg command or observation post tank, Sturmpanzer IV Brummbär (SdKfz 167) and StuG IV (SdKfz 167) assault guns, and Jagdpanzer IV (SdKfz 162) tank destroyer. The chassis was also used for the Hornisse and Nashorn self-propelled anti-tank guns, and Hummel self-propelled howitzer. Anti-tank plaforms included the 3.7cm FlaK, Wirbelwind, and Ostwind I. Non-combat variants included the Brükenleger IV bridgelayer and the Bergepanzer IV recovery vehicle along with numerous experimental or prototype versions. Many variants are described separately.