Sultan Zainal Abidin III Muadzam Shah ibni Almarhum Sultan Ahmad Muadzam Shah II, KCMG, (12 April 1866 – 26 November 1918) was Sultan and Yang di-Pertuan Besar of the state of Terengganu from 1881 to 1918. Succeeding on the death of his father Sultan Ahmad, under his reign Terengganu became a British protectorate under the Anglo-Siamese Treaty of 1909. In 1911, Sultan Zainal Abidin III issued Terengganu's first constitution. He died in Kuala Terengganu on 26 November 1918, aged 52, after a nearly 37-year reign and was buried in the Zainal Abidin mosque. He was succeeded by his son, Muhammad Shah II.