Beyoğlu (ˈbejoːɫu, بكاوغلی) is a municipality and district of Istanbul Province, Turkey. Its area is 9 km2, and its population is 225,920 (2022). It is on the European side of İstanbul, Turkey, separated from the old city (historic peninsula of Constantinople) by the Golden Horn. It was known as the region of Pera (Πέρα, meaning "Beyond" in Greek) surrounding the ancient coastal town Galata which faced Constantinople across the Horn. Beyoğlu continued to be named Pera during the Middle Ages and, in western languages, into the early 20th century.
According to the prevailing theory, the Turkish name of Pera, Beyoğlu, meaning "Son of a Bey" in Ottoman Turkish, is a modification by folk etymology of the Venetian title of Bailo. The 15th century ambassador of Venice in Istanbul, Andrea Gritti, had a mansion in this area. Located further south in Beyoğlu and originally built in the early 16th century, the "Venetian Palace" was the seat of the Bailo. The original palace building was replaced by the existing one in 1781, which later became the Italian Embassy following Italian unification in 1861, and the Italian Consulate in 1923, when Ankara became the capital of the Republic of Turkey. Once a predominantly Christian (Armenians, Greeks, and Turkish Levantine) neighbourhood, its population today mostly consists of Turks and Kurds who moved there after the Republic of Turkey was founded in 1923 and after Istanbul pogrom in 1955.
The district encompasses other neighborhoods located north of the Golden Horn, including Galata (the medieval Genoese citadel from which Beyoğlu itself originated, which is today known as Karaköy), Tophane, Cihangir, Şişhane, Tepebaşı, Tarlabaşı, Dolapdere and Kasımpaşa, and is connected to the old city center across the Golden Horn through the Galata Bridge, Atatürk Bridge and Golden Horn Metro Bridge. Beyoğlu is the most active art, entertainment and nightlife centre of Istanbul.
The area now known as Beyoğlu has been inhabited since Byzas founded the City of Byzantium in the 7th century BC, and predates the founding of Constantinople.