The Panzer I was a light tank produced in Nazi Germany in the 1930s. Its name is short for Panzerkampfwagen I (German for "armored fighting vehicle mark I"), abbreviated as PzKpfw I. The tank's official German ordnance inventory designation was Sd.Kfz. 101 ("special purpose vehicle 101").
Design of the Panzer I began in 1932 and mass production began in 1934. Intended only as a training tank to introduce the concept of armored warfare to the German Army, the Panzer I saw combat in Spain during the Spanish Civil War, in Poland, France, the Soviet Union and North Africa during the Second World War, and in China during the Second Sino-Japanese War. Experiences with the Panzer I during the Spanish Civil War helped shape the German Panzerwaffe's invasion of Poland in 1939 and France in 1940. By 1941, the Panzer I chassis design was used as the basis of tank destroyers and assault guns. There were attempts to upgrade the Panzer I throughout its service history, including by foreign nations, to extend the design's lifespan. It continued to serve in the Spanish Armed Forces until 1954.