Bābak Khorram-Din (Formally known as "Pāpak" meaning "Young Father")795, according to some other sources 798— January 838) is one of the main Persian revolutionary leaders of the Iranian[ Khorram-Dinān ("Those of the joyous religion"), which is a local freedom movement fighting the Abbasid Caliphate.

Khorramdin appears to be a compound analogous to dorustdin "orthodoxy" and Behdin "Good Religion" (Zoroastrianism), and are considered an offshoot of neo-Mazdakism.

Babak's Iranianizing rebellion, from its base in Azerbaijan in northwestern Iran, calls for a return of the political glories of the Iranian past.

The Khorramdin rebellion of Babak spreads to the Western and Central parts of Iran and lasts more than twenty years before it is defeated.

Babak's uprising shows the continuing strength in Azerbaijan of ancestral Iranian local feelings.