Muhammad III as-Sadiq GCB (Arabic: محمد الثالث الصادق; February 1813 – 27 October 1882) commonly known as Sadok Bey (Arabic: الصادق باي), was the Husainid Bey of Tunis from 1859 until his death. Invested as Bey al-Mahalla (Heir Apparent) on 10 June 1855, he succeeded his brother Muhammad II ibn al-Husayn on 23 September 1859. Named as divisional General in the Imperial Ottoman Army on 10 June 1855, he was promoted to the rank of Marshal on 10 December 1859.