Horst Prinzbach (20 July 1931 in Haslach im Kinzigtal – 18 September 2012 in Freiburg im Breisgau) was a German chemist and professor emeritus. Prinzbach studied chemistry at the University of Freiburg and received his PhD under Arthur Lüttringhaus. He joined William von Eggers Doering at Yale University for postdoctoral work. In 1962 he completed his habilitation at Freiburg with a dissertation on sesquifulvalenes. In 1965 he became a professor of organic chemistry at the University of Lausanne, Switzerland, and in 1969 he became a full professor in organic chemistry at Freiburg.