Gaziosmanpaşa (Turkish: [ɡaːziosˈmanpaʃa]; old name: Taşlıtarla) is a developing working class municipality (belediye) and district of Istanbul, Turkey, on its European side.

The district was named after Gazi Osman Pasha (1832–1900), a prominent Ottoman general who was active in the Balkans.

The area was empty, rocky pasture until the 1950s when immigrants from the Balkans (especially from Bulgaria, Yugoslavia and Western Thrace) settled here.

As the area has grown without sufficient control or regulations the city is still struggling to put in schools and other infrastructure throughout Gaziosmanpaşa to support the population, while industrial development is taking place too.

The area itself suffers from unemployment despite the industry coming in, and the main employers are small workshops producing light fittings, electrical goods, clothing, lathe and metalwork and car repairs.