Franz Hartmann (1838-1912), was a German medical doctor, Theosophist, occultist, geomancer, astrologer, and author. He was an associate of Helena Blavatsky and was Chairman of the Board of Control of the Theosophical Society Adyar. He collaborated with the mystic Carl Kellner. He wrote articles on yoga and popularized the subject within Germany.
As "one of the most important theosophical writers of his time", his works include several books on esoteric studies and biographies of Jakob Böhme and Paracelsus. He translated the Bhagavad Gita into German and was the editor of the journal Lotusblüten. In 1896 he founded a German Theosophical Society. He also supported the Guido-von-List-Society (Guido-von-List-Gesellschaft).
According to Theodor Reuss he was one of the original founders of the magical order that would later be known as Ordo Templi Orientis, along with Reuss and Carl Kellner.