Robert Kienböck (January 11, 1871 – September 8, 1953) was an Austrian radiologist who was a native of Vienna.
In 1895 he earned his medical doctorate at the University of Vienna, and spent the next year abroad. He returned to Vienna as an assistant to Leopold von Schrötter (1837-1908), a laryngologist, and began working in the new science of radiology. Several years later he became head of the radiological department of the Vienna General Hospital. With Guido Holzknecht (1872-1931) he was co-founder of the Wiener Röntgengesellschaft (Vienna Radiology Society). He was elected president of the Austrian Radiology Society in 1934 and honorary president of that body after the Second World War.
Kienböck was a pioneer in the use of x-ray technology for medical diagnosis and therapy. He specialized in research of skeletal diseases and treatment through radiology. In 1910 he described a disorder which consisted of breakdown of the lunate bone in the wrist. He called the disorder lunatomalacia, which is now known as Kienböck's disease. Kienböck published his findings in a treatise titled Über traumatische Malazie des Mondbeins und ihre Folgezustände (Traumatic Malacia of the Lunate and its Consequences).