Büyükçekmece is a municipality and district located in the Istanbul Province of Turkey. Situated on the coast of the Sea of Marmara on the European side of the city, it covers a total area of 173 km2. The district has a population of 277,181 as of 2022.
Historically known as Athyras, the area is characterized largely as an industrial zone. It is currently governed by Mayor Ahmet Şahin of the CHP.