Robert Michaelis von Olshausen (July 3, 1835 – February 1, 1915) was a German obstetrician and gynecologist who was a native of Kiel.
In 1857 he earned his doctorate from Königsberg, and subsequently was a medical assistant in Berlin and Halle an der Saale. In 1863 he became a professor at Halle, and in 1887 returned to Berlin as successor to Karl Ludwig Ernst Schroeder (1838–1887) as director of the university Frauenklinik. He was the son of Justus Olshausen (1800–82), who was a professor of Oriental languages at the University of Kiel.
Robert Olshausen is credited with introducing new obstetrical techniques into surgery. He was publisher of the journal Zeitschrift für Geburtshilfe und Gynäkologie, and with Johann Veit (1852–1917) edited Karl Schroeder's Lehrbuch der Geburtshülfe.