Hermann Vallentin (24 May 1872 – 18 September 1945) was a German actor born in Berlin. He was the son of a Jewish timber merchant and factory owner, Felix Vallentin. He was the older brother of actress Rosa Valetti. After training as an actor at the Royal Theatre in Berlin with Max Grube and Hans Oberländer, he received his first engagement at the Central-Theatre in Berlin in the 1895/96 season. In the next few years, appearances on various Berlin stages followed.

From 1914, Vallentin was also a film actor. He mostly embodied fatherly figures, patriarchs and directors, but also small-minded philistines. In the 1931 film version of Der Hauptmann von Köpenick, he played the uniform tailor Adolph Wormser.

The seizure of power by the Nazis in 1933, ended his film career abruptly. In 1933 Vallentin, emigrated to Czechoslovakia, where he appeared on German language stages in Ústí and Prague. In 1938 he left for Switzerland and worked at the Stadttheater Basel and the Schauspielhaus Zürich. In 1939 he emigrated to Mandatory Palestine and settled in Tel Aviv. Not being able to speak Hebrew, he retired from acting altogether. In Tel Aviv, he lectured, read poetry and was a sporadic anchorman for German-language news on the Palestine Broadcasting Service (PBS). He died in Tel Aviv in 1945, aged 73.