The Knoller C.II was a reconnaissance aircraft built in Austria-Hungary during World War I for use by the Austro-Hungarian army. It was a conventional biplane design with staggered wings, and seated the pilot and observer in tandem in an open cockpit. Like Knoller's preceding C.I design, the upper wing was swept back, but not as far as it had been on the earlier aircraft. The structure was wooden throughout, with the wings skinned in fabric and the fuselage in plywood. The interplane struts were made of steel and arranged in a warren truss configuration.
Production was undertaken in three batches of 25 aircraft, one each by Aviatik, Lohner, and WKF, with the first machine delivered to the Army in September 1916. On 10 February the following year, the wings of this aircraft collapsed in flight and its crew was killed in the ensuing crash. This incident led to production and further flying of the type to be suspended. A single example is preserved at the National Technical Museum in Prague.