The Leopard (or Leopard 1) is a main battle tank designed and produced by Porsche in West Germany that first entered service in 1965. Developed in an era when HEAT warheads were thought to make conventional heavy armour of limited value, the Leopard focused on firepower in the form of the German-built version of the British L7 105-mm gun, and improved cross-country performance that was unmatched by other designs of the era.

The design started as a collaborative project during the 1950s between West Germany and France, and later joined by Italy,^[1] but the partnership ended shortly after and the final design was ordered by the Bundeswehr, with full-scale production starting in 1965. In total, 6,485 Leopard tanks have been built, of which 4,744 were battle tanks and 1,741 were utility and anti-aircraft variants, not including 80 prototypes and pre-series vehicles.

The Leopard quickly became a standard of many European militaries, and eventually served as the main battle tank in over a dozen countries worldwide, with West Germany, Italy and the Netherlands being the largest operators until their retirement. Since 1990, the Leopard 1 has gradually been relegated to secondary roles in most armies. In the German Army, the Leopard 1 was completely phased out in 2003 by the Leopard 2, while Leopard 1-based vehicles are still widely used in utility roles. The Leopard 2 has replaced the Leopard 1 in service with many other nations as well, with derived vehicles using the Leopard 1 hull still seeing service. Currently, the largest operators are Greece, with 520 vehicles, Turkey, with 397 vehicles and Brazil with 378 vehicles. Most of these vehicles have been upgraded with various improvements to armour, firepower and sensors to maintain their ability to engage modern threats.