Isidor Hilberg (May 28, 1852, at Byelaya Tzerkov, Russian Empire – October 28, 1919, in Vienna), was a classical scholar in Austria-Hungary.
In 1856 he went with his parents to Vienna, where he received his early education.
Subsequently he studied classical philology at the University of Vienna under Vahlen, Gomperz, Emanuel Hoffmann, and Hartel (Ph.D. 1874).
In 1875, he studied for half a year in Italy, and became privatdozent in classical philology at the University of Vienna in 1877.
He is now best known for his three-volume edition of the letters of St. Jerome in the Corpus Scriptorum Ecclesiasticorum Latinorum.