The Rumpler D.I (factory designation 8D1) was a fighter-reconnaissance aircraft produced in Germany at the end of World War I. It was a conventional single-bay biplane with wings of unequal span braced by I-struts. It featured an open cockpit and a fixed, tailskid undercarriage. The upper wing was fitted with aerodynamically balanced ailerons and fuselage had an oval cross-section.
The D.I had a protracted development through the course of 1917, with at least six different development prototypes built before Rumpler settled on a final design in 1918 in time for the Idflieg's D-type competition at Adlershof. Two 8D1s participated, powered by Mercedes D.III engines. Another one participated in the follow-on competition in autumn, this time with a BMW engine.
The Idflieg approved the type for production and issued the designation D.I, but only a small number were produced; the war was practically over and none saw operational service.