| Karl Gottfried Hagen | |
| Birth Date: | 24 December 1749 |
| Birth Place: | Königsberg, Prussia |
| Death Place: | Königsberg |
| Nationality: | German |
| Field: | chemist |
| Work Institutions: | University of Königsberg |
Karl Gottfried Hagen (24 December 1749 – 2 March 1829) was a German chemist.
Hagen was born and died in Königsberg, Prussia.
He founded the first German chemical laboratory at the University of Königsberg, thus establishing the scientific discipline of pharmaceutical chemistry in Germany. He worked as a professor in the field of physics, chemistry and mineralogy.
His daughter Johanna married the astronomer Friedrich Wilhelm Bessel, and his daughter Louise Florentine married the physicist Franz Ernst Neumann. He was father of Carl Heinrich Hagen and Ernst August Hagen, and grandfather of Hermann August Hagen and Adolf Hermann Hagen.