Theodor Benfey (January 28, 1809 - June 26, 1881), German philologist was the son of a Jewish trader at Nörten, near Göttingen.

Although originally destined for the medical profession, his taste for philology was awakened by a careful instruction in Hebrew which he received from his father. After brilliant studies at Göttingen he spent a year at Munich, where he was greatly impressed by the lectures of Schelling and Thiersch, and afterwards settled as a teacher in Frankfurt.

His pursuits were at first chiefly classical, and his attention was diverted to Sanskrit by an accidental wager that he would learn enough of the language in a few weeks to be able to review a new book upon it. This feat he accomplished, and rivalled in later years when be learned Russian in order to translate VP Vasilev's work on Buddhism. For the time, however, his labours were chiefly in classical and Semitic philology. At Göttingen, whither be had returned as Privatdozent, he wrote a little work on the names of the Hebrew months, proving that they were derived from the Persian, prepared the great article on India in Ersch and Gruber's Encyclopaedia, and published from 1839 to 1842 the Lexicon of Greek Roots which gained him the Volney prize of the Institute of France.

From this time his attention was principally given to Sanskrit. He published in 1848 his edition of the Sama-veda; in 1852-1854 his Manual of Sanskrit, comprising a grammar and chrestomathy; in 1858 his practical Sanskrit grammar, afterwards translated into English; and in 1859 his edition of the Pantscha Tantra, with an extensive dissertation on the fables and mythologies of primitive nations. All these works had been produced under the pressure of poverty, the government, whether from parsimony or from prejudice against a Jew, refusing to make any substantial addition to his small salary as extra-professor at the university.

At length, in 1862, the growing appreciation of foreign scholars shamed it into making him an ordinary professor, and in 1866 Benfey published the laborious work by which he is on the whole best known, his great Sanskrit-English Dictionary. In 1869 he wrote a history of German philological research, especially Oriental, during the 19th century. In 1878 his jubilee as doctor was celebrated by the publication of a volume of philological essays dedicated to him and written by the first scholars in Germany. He had designed to close his literary labours by a grammar of Vedic Sanskrit, and was actively preparing it when he was interrupted by illness, which terminated in his death at Göttingen.

A collection of his various writings was published in 1890, prefaced by a memoir by his son. Among his pupils was James Murdoch.