Abdul Mejid I (Ottoman Turkish: عبد المجید اول, romanized: ʿAbdü'l-Mecîd, Turkish: I. Abdülmecid; 25 April 1823 – 25 June 1861) was the 31st sultan of the Ottoman Empire. He succeeded his father Mahmud II on 2 July 1839.

Abdulmejid's greatest achievement was the announcement of the Tanzimat Edict upon his accession, prepared by his then Foreign Minister Mustafa Reshid Pasha, which effectively began the Tanzimat era, or era of reorganization, in the Ottoman Empire. He was a mild-mannered monarch, giving the Sublime Porte the autonomy needed for its reform projects. One of the main goals of the Tanzimat was to encourage Ottomanism among the millets to stop rising nationalist movements within the empire, but despite new laws and reforms to integrate non-Muslims and non-Turks more thoroughly into Ottoman society, in the long term, the movement failed.

Abdulmejid forged alliances with the major powers of Western Europe, namely the United Kingdom and France, which fought alongside the Ottoman Empire in the Crimean War against Russia. During the Congress of Paris on 30 March 1856, the Ottoman Empire was officially included among the Concert of Europe. Abdulmejid suddenly died of tuberculosis and was succeeded by his half-brother, Abdul Aziz.