Mazyar (Middle Persian: Māh-Izād; Mazandarani/Persian: مازیار, romanized: Māzyār) was an Iranian prince from the Qarinvand dynasty, who was the ruler (ispahbadh) of the mountainous region of Tabaristan from 825/6 to 839.

For his resistance to the Abbasid Caliphate, Mazyar is considered one of the national heroes of Iran by twentieth-century Iranian nationalist historiography.

Mazyar belonged to the Qarinvand dynasty, which was descended from Sukhra, a powerful magnate from the House of Karen, who was the de facto ruler of the Sasanian Empire from 484 to 493.

There he met one of his astrologers, Yahya ibn al-Munajjim, a Persian who had recently converted to Islam and belonged to the Banu Munajjim family.

Mazyar soon also embraced Islam,[a] and al-Ma'mun gave him the title of "Servant of the Commander of the Faithful" (mawlā amīr al-muʾminīn) and the Muslim name of Abu'l-Hasan Muhammad.

In 822/3, Mazyar returned to Tabaristan with Abbasid reinforcements, and began to deal with his enemies—he had his brother Quhyar exiled, and did the same to Shahriyar I's son Qarin I, who was his nephew.

[2] Mazyar now began constructing mosques in several towns, and successfully plundered the territories of the Daylamites, and had a large number of them resettled in the border place of Muzn.

However, when the Tahirid ruler Abdallah ibn Tahir demanded the payment of the land tax (kharaj) from Mazyar, the latter refused.

Feeling threatened, Mazyar rebelled against the Abbasid Caliphate, an act which was widely supported by the native Zoroastrians [6] and the Abbasid-controlled border regions.