Islamic revival (or Tajdid, also Sahwah) (Arabic: التجديد الإسلامي aẗ-ẗajdid l-ʾIslāmiyyah, also Arabic: الصحوة الإسلامية aṣ-Ṣaḥwah l-ʾIslāmiyyah, "Islamic awakening") refers to a revival of the Islamic religion. Revivals (ẗajdid) have traditionally been a periodic occurrence throughout the Islamic world, led by a "reviver" or mujaddid who arrives at the beginning of every (Islamic) century, according to one hadith. The mujaddid will "fear none but God, and put a stop to (religious) "ignorance", "false innovations" and "a deterioration in following of the Sunnah".
Preachers and scholars who have been described as revivalists or mujaddideen in the history of Islam include Ahmad Sirhindi, Ibn Taymiyyah, Shah Waliullah, and Muhammad ibn Abd-al-Wahhab. In the 20th century, Islamist leaders Hassan al-Banna, Abul Ala Maududi, and Ruhollah Khomeini, have been described as such, and the terms "Islamist" and "Islamic revivalist" have often been used interchangeably.
The most recent Islamic revival is thought to have begun roughly sometime in the 1970s (although strong movements began earlier in the century in Egypt and South Asia) and is a reversal of the "Westernization" approach common in Arab and Asian governments earlier in the 20th century. It followed the quadrupling of oil prices in the mid-1970s – which financed billions of dollars of conservative Islamic books, scholarships, fellowships, and mosques around the world; and the 1979 Iranian Revolution which undermined the assumption that Westernization strengthened Muslim countries and was the irreversible trend of the future.