| Johann Mulzer | |
| Birth Date: | 5 August 1944 |
| Birth Place: | Prien, Germany |
| Field: | Organic chemistry |
| Work Institution: | University of Düsseldorf 1982–1984 Free University of Berlin 1984–1995 University of Frankfurt 1995–1996 University of Vienna 1996– |
| Alma Mater: | University of Munich |
| Prizes: | Gottfried Wilhelm Leibniz Prize 1994 |
Johann Hermann Wolfgang Mulzer is a German organic chemist, best known for his work in total synthesis. Since 1996, he has been a professor of chemistry at the University of Vienna (Universität Wien).