Karl Hecker (8 May 1827 – 14 December 1882) was a German gynecologist and obstetrician born in Berlin. He was the only son of medical historian Justus Hecker (1795–1850).
He studied medicine at the Universities of Berlin, Heidelberg, Paris and Vienna, receiving his doctorate in 1848 from Berlin. In 1851 he became an assistant at the clinic of obstetrics at the Berlin-Charité under Dietrich Wilhelm Heinrich Busch (1788–1858). Here he gained his habilitation in 1853 with a thesis involving retroverted gravid uterus (De retroversione uteri gravidi).
In 1858 he was an associate professor of obstetrics at the University of Marburg, and during the following year accepted an appointment as a gynecologist at the University of Munich. At Munich he was also director of the municipal district maternity hospital and school for midwives. In 1874/75 he served as university rector. From 1877 he worked with Carl Siegmund Franz Credé (1819–1892) and Alfred Hegar (1830–1914) for the creation of an independent gynecological society, but it wasn't until 1885, three years after his death, when the Deutsche Gesellschaft für Gynäkologie was established.
Hecker was a son-in-law to politician Johann Caspar Bluntschli (1808–1881).