Royal Prussian Jagdstaffel 66, commonly abbreviated to Jasta 66, was a "hunting group" (i.e., fighter squadron) of the Luftstreitkräfte, the air arm of the Imperial German Army during World War I.

The squadron would score over 97 aerial victories during the war, including seven observation balloons downed.

The unit's victories came at the expense of five pilots killed in action, one who died in captivity, and two taken prisoner of war.

[1] Jasta 66 was founded on 27 January 1918 at Hannover, Germany, at Fliegerersatz-Abteilung ("Replacement Detachment") 5.

Rudolf Windisch scored the unit's first victory on 15 March 1918.