Hermann Clemenz (23 January 1846 – 28 March 1908) was an Estonian chess master.
Born in Dorpat (Tartu), Estonia (then Russian Empire), he began his chess career in his native town, then lived in St. Petersburg, where he participated in several tournaments. In Dorpat, he won some games against Eisenschmidt in the 1860s. In St. Petersburg he took 4th in 1876 (Andreas Ascharin won), took 4th in 1877 (Mikhail Chigorin won), and took 3rd, behind Sergey Lebedev and Grigory Helbach, in 1901.
His name is attached to the Clemenz Opening; 1.h3. He played this opening in St. Petersburg in 1873.