Abu l-Abbas al-Fadl ibn Sahl ibn Zadhanfarukh al-Sarakhsi (; died 818), titled Dhu 'l-Ri'āsatayn ("the man of the two headships"), was a famous Persian vizier of the Abbasid era in Khurasan, who served under Caliph al-Ma'mun (r. 813–832). He played a crucial role in the civil war between al-Ma'mun and his brother al-Amin (r. 809–813), and was the vizier of the Abbasid Caliphate until 817.