Mustafa III — the reformer
Mustafa III, son of Ahmed III, reigned from 1757 to 1774 and spent it trying to rebuild Ottoman military capability. He recruited European advisers, reorganized artillery, and founded an engineering school for the navy — the beginning of a technical-education tradition that later Ottoman reformers built on. In 1768 he went to war with Russia, and the war went badly, including the destruction of the Ottoman fleet at Çeşme in 1770. He died in January 1774, months before the humiliating peace that ended it.
Mustafa IV — a reign of a year
Mustafa IV was raised to the throne in 1807 by the revolt that overthrew his cousin Selim III, whose New Order army had made him enemies among the janissaries. In 1808 an army from the Danube provinces under Alemdar Mustafa Pasha marched on Istanbul to restore Selim; Selim was killed before he could be reached, and Alemdar enthroned the young Mahmud II instead. Mustafa IV was deposed and executed later that year — the last Ottoman sultan to meet that end.
Şehzade Mustafa — the prince who was mourned
The most famous Ottoman Mustafa never reigned at all. Şehzade Mustafa (1515–1553), eldest son of Suleiman the Magnificent, was an admired and experienced provincial governor widely expected to succeed his father. In 1553, on campaign in the east, he was executed on Suleiman's orders amid accusations of plotting. The army's grief was immediate and public, and the poet Taşlıcalı Yahya's elegy for him became one of the best-known laments in Ottoman literature. He remains a fixture of Turkish historical drama and fiction — as noted in Mustapha in music, film and literature.
Beyond the throne: two grand viziers named Mustafa shaped Ottoman history as decisively as the sultans — Kara Mustafa Pasha, who commanded the failed siege of Vienna in 1683, and Alemdar Mustafa Pasha, the kingmaker of 1808.
Ottoman prestige is a large part of why the name spread across Anatolia and the Balkans; the full route is traced on the origin page, and the Turkish spelling that these rulers' names take in English is explained under Mustafa. The most famous Turkish bearer of all came later: Mustafa Kemal Atatürk. See also Ottoman scholars named Mustafa and the full list of famous Mustaphas.