Wilhelm Jensen (15 February 1837 - 24 November 1911) was a German writer.

He was born at Heiligenhafen in Holstein, the son of a local Danish magistrate, who came of old patricial Frisian stock. After attending the classical schools at Kiel and Lübeck, Jensen studied medicine at the universities of Kiel, Wurzburg and Breslau. He, however, abandoned the medical profession for that of letters, and after engaging for some years in individual private study proceeded to Munich, where he associated with men of letters. After a residence in Stuttgart (1865-1869), where for a short time he conducted the Schwabische Volks-Zeitung , he became editor in Flensburg of the Norddeutsche Zeitung . In 1872 he again returned to Kiel, lived from 1876 to 1888 in Freiburg im Breisgau, and since 1888 has been resident in Munich.

Jensen was perhaps the most fertile of German writers of fiction of his era, more than one hundred works having proceeded from his pen; but only comparatively few of them have caught the public taste; such are the novels, Karin von Schweden (Berlin, 1878); Die braune Erica (Berlin, 1868); and the tale, Die Pfeifer von Dusenbach, Eine Geschichte aus dem Elsass (1884). Among others may be mentioned: Barthenia (Berlin, 1877); Gtz und Gisela (Berlin, 1886); Heimkunft (Dresden, 1894); Aus See und Sand (Dresden, 1897); Luv und Lee (Berlin, 1897); and the narratives, Aus den Tagen der Hansa (Leipzig, 1885); Aus stiller Zeit (Berlin, 1881-1885); and Heimath (??). Jensen also published some tragedies, among which Dido (Berlin, 1870) and Der Kampf frs Reich (Freiburg im Br., 1884) may be mentioned.