The Panzer 61 was a Swiss Cold War era medium tank later reclassified as a second-generation main battle tank. The tank had a weight of 36.5 tons and was powered by a 630 hp diesel engine, which gave it a top road speed of 50 km/h (31 mph). The primary armament of the Panzer 61 was a 105 mm main gun.
During the early 1950s the Swiss Army tried to buy modern tanks to reinforce the armoured forces which, due to the war in Korea, proved to be impossible. As a stop-gap solution, the Swiss army purchased AMX-13 light tanks from France and decided to develop a domestic medium tank.
The first prototype and production vehicles were designated Panzer 58. The first Panzer 58 prototype was armed with a domestic 90mm rifled gun, the second Panzer 58 was fitted with a British 84 mm calibre Ordnance QF 20 pounder and the third prototype as well as the production model was fitted with a Royal Ordnance L7 105mm rifled gun.
The Panzer 58 served similarly to a preproduction model of the improved Panzer 61, and in 1961 the Swiss parliament approved production of 150 Panzer 61s. The vehicles were delivered between 1965 and 1967, produced at the Eidgenoessische Konstruktionswerkstaette (today RUAG Land Systems) facility at Thun.