The Muslim conquest of Persia, also called the Muslim conquest of Iran, the Arab conquest of Persia, or the Arab conquest of Iran, was a major military campaign undertaken by the Rashidun Caliphate between 632 and 654. As part of the early Muslim conquests, which had begun under Muhammad in 622, it led to the fall of the Sasanian Empire and the eventual decline of Zoroastrianism, which had been predominant throughout Persia as the nation's official religion. The persecution of Zoroastrians by the early Muslims during and after this conflict prompted many of them to flee eastward to India, where they were granted refuge by various kings.

The Sasanian Empire or Sassanid Empire, officially known as Eranshahr, was the last Iranian empire before the early Muslim conquests of the 7th to 8th centuries. Named after the House of Sasan, it endured for over four centuries, from 224 to 651, making it the second longest-lived Persian imperial dynasty after the Arsacids of the Parthian Empire.