The Junkers J 5 was a designation assigned to several fighter aircraft designs.
In early 1917, Junkers developed at least two cantilever wing monoplane fighter aircraft designs based on the J4.
The first design, known as the J 5I, was to have a Siemens Sh2 or Oberursel UR.II engine behind the cockpit.
The second design was to have the engine in front of the pilot.
A third design was also developed under the designation J 5III (later J 6) with a Mercedes D.IIIa and a parasol wing.