The Al-Hadi Mosque or Al-Imam Al-Hadi Mosque () is one of the historical mosques of the ancient city of Sa'ada, Yemen. It is located east-west of the city. It was built in around 897, and named after Imam Yahya Bin Al-Hussein, the founder of the Imams of Yemen state. The mosque became the oldest place for the teaching of Zaidi maddhab in the Arabian Peninsula.