Royal Prussian Jagdstaffel 4, commonly abbreviated to Jasta 4, was a "hunting group" of the Luftstreitkräfte, the air arm of the Imperial German Army during World War I. The unit would score 192 confirmed victories; in turn, it would suffer 11 killed in action, 9 wounded in action, and two taken prisoner of war. It was one of the units in the famed Flying Circus.

Jagdgeschwader I of World War I, was a fighter wing of the German Luftstreitkräfte, comprising four Jastas. The first unit of its type formed under that classification, JG I was formed on 24 June 1917, with Manfred von Richthofen as commanding officer, by combining Jastas 4, 6, 10 and 11. JG I became known as "The Flying Circus" or "Richthofen's Circus" because of the bright colours of its aircraft, and perhaps also because of the way the unit was transferred from one area of Allied air activity to another – moving like a travelling circus in trains, and frequently setting up in tents on improvised airfields.