The Istanbul riots (Greek: Σεπτεμβριανά Septemvriana, "Events of September"; Turkish: 6–7 Eylül Olayları, "Events of September 6–7", sometimes known as the "Istanbul pogrom"), were organized mob attacks directed primarily at Istanbul's Greek minority on 6–7 September 1955. The riots were orchestrated by the Turkish government of the time under the Prime Minister Adnan Menderes. The events were triggered by the false news that the Turkish consulate in Thessaloniki, north Greece—the house where Mustafa Kemal Atatürk had been born in 1881—had been bombed the day before. A bomb planted by a Turkish usher at the consulate, who was later arrested and confessed, incited the events. The Turkish press almost fully under Menderes' control, conveying the news in Turkey was silent about the arrest and instead insinuated that Greeks had set off the bomb.

A Turkish mob, most of which had been trucked into the city in advance, assaulted Istanbul’s Greek community for nine hours. Although the mob did not explicitly call for Greeks to be killed, over a dozen people died during or after the attacks as a result of beatings and arson. Jews and Armenians were also harmed.

Istanbul (Turkish: İstanbul) is the largest city in Turkey, forming the country's economic, cultural, and historical heart. With a population of 13.4 million, the city is at the center of the second-largest urban area in Europe after Moscow, and among the world's largest cities by population within city limits. Istanbul's vast area of 5,343 square kilometers (2,063 sq mi) is coterminous with Istanbul Province, of which the city is considered capital. Straddling the Bosphorus—one of the world's busiest waterways—in northwestern Turkey, between the Sea of Marmara and the Black Sea, Istanbul is a transcontinental city, with one third of its population living in Asia but its commercial and historical center in Europe.

Founded around 660 BC as Byzantium on the Seraglio Point, the city now known as Istanbul developed to become one of the most significant cities in history. For nearly sixteen centuries following its reestablishment as Constantinople in 330 AD, it served as the capital of four empires — the late classical Roman Empire (330–395), the Eastern Roman ("Byzantine") Empire (395–1204 and 1261–1453), the Latin Empire (1204–1261), and the Ottoman Empire (1453–1922). It was instrumental in the advancement of Christianity during Roman and Byzantine times, before the Ottomans conquered the city in 1453 and transformed it into an Islamic stronghold from which the last caliphate ruled. Although the Republic of Turkey established its capital elsewhere, in Ankara, remnants of Istanbul's previous central role still remain highly visible across the city, with palaces and imperial mosques lining its hills.