| Unit Name: | Jasta 39 |
| Dates: | 1917–1918 |
| Country: | German Empire |
| Branch: | Luftstreitkräfte |
| Type: | Fighter squadron |
| Battles: | World War I Western Front Italian Front |
Royal Prussian Jagdstaffel 39, commonly abbreviated to Jasta 39, was a "hunting group" (i.e., fighter squadron) of the Luftstreitkräfte, the air arm of the Imperial German Army during World War I. The unit would score 68 aerial victories during the war, including 14 observation balloons downed. The squadron's victories came at the expense of seven pilots killed in action, one killed in a flying accident, five wounded in action, and one taken prisoner of war.
Jasta 39 was founded on 30 June 1917 at Fliegerersatz-Abteilung (Replacement Detachment) 15, Hannover, Germany. It held its first formation 2 August 1917, under its original commander, Karl August Raben. It would serve until war's end, when the Luftstreitkräfte was disbanded.
Jasta 39 opened combat operations in support of Armee-Abteilung B on 15 August 1917. On 15 September 1917, it was transferred to Italy, where it would score 41 aerial victories. The squadron would return to France in March 1918, and serve there until war's end.
Jasta 39 operated Albatros D.III and Albatros D.V fighters while in Italy. It is not known what other aircraft were used.