Robert Knud Friedrich Pilger (3 July 1876, in Helgoland – 1 September 1953, in Berlin) was a German botanist, who specialised in the study of conifers.
He collected plants in the Mato Grosso of Brazil, and from 1945 to 1950 was director of the botanical garden at Berlin-Dahlem.
The genera Pilgerodendron Florin (Cupressaceae) and Pilgerochloa Eig (Poaceae) are named in his honour.