Gustav Leffers (2 January 1895 –27 December 1916) was a German flying ace in World War I, credited with 9 victories.

In July 1914, just prior to the start of the First World War, he returned from a cruise to the United States.

Starting as a Gefreiter, Leffers rose rapidly through the ranks to become a leutnant der reserve on the basis of his excellent performance in reconnaissance roles flying LVG B type aircraft.

He received the Royal House Order of Hohenzollern after his sixth victory on 31 August 1916, and the Pour le Merite in November 1916 after his eighth win.

[4] On 27 December Lt. Leffers was shot down and killed in combat with FE-2b's of No 11 Squadron RFC, the most likely victors being the crew of Capt.