The Legión Cóndor (Condor Legion in English) was a unit of Nazi Germany's air force which was sent as volunteers to support the Nationalists (i.e., Francisco Franco) in the Spanish Civil War.

The first units of the Condor Legion arrived in Spain at the beginning of August 1936. German military assistance expanded rapidly in the succeeding months; at the beginning of November the Legion consisted of 100 airplanes and 5,000 men under the command of Hugo Sperrle (1885-1953). By rotation of the contingents, a total of approximately 20,000 Germans served in Spain. Despite paying lip service to Non-Intervention , Adolf Hitler justified this intervention as part of a "fight against the Bolshevism".

The Spanish Civil War provided the Germans with the opportunity to test new weapons and tactics - the Messerschmitt Bf 109 fighter and Heinkel He 111 medium bomber first saw active service in the Condor Legion. These two aircraft would be the mainstay of the Luftwaffe during the invasion of France and the Battle of Britain in 1940. The Germans also realized that the days of the biplane fighter were over, the Heinkel He 51 fighter with which the Condor Legion had been equipped initially was switched to a ground attack role and then became a trainer. The Condor Legion also included non-aircraft units. There were panzer crews with Panzerkampfwagen I and sailors who trained Franco's naval forces. The Germans also tested their 88mm heavy anti-aircraft artillery which they used to destroy republican tanks, fortifications, and planes.

The bombing of the town of Guernica on 26 April 1937 brought fierce international condemnation, inspiring Pablo Picasso's painting "Guernica", which dramatized the suffering the civilian population. Although not the first town to be attacked, the sheer scale of the destruction (with over 1000 killed and 60% of the houses destroyed) was a clear foretaste of what would happen to many cities during the Second World War.

Various sympathetic writers participated in condemning the scarcely concealed interference of Germany and Italy. An example was Heinrich Mann, who appealed from exile in France with the slogan "German soldiers! A rogue sends you to Spain!" in response to the Legion's involvement.

See also

• Spanish Civil War: Basque
• Aerotech: Aerial bombing of cities, Flying ace
• Other: Henschel Hs 129