Kadıköy is a municipality and district on the Asian side of Istanbul Province, Turkey. Its area is 25 km2, and its population is 467,919 (2023). It is a large and populous area in the Asian side of Istanbul, on the northern shore of the Sea of Marmara. It partially faces the historic city centre of Fatih on the European side of the Bosporus. It is bordered by the districts of Üsküdar, to the northwest, Ataşehir, to the northeast, and Maltepe, to the southeast.

Bağdat Avenue is one of the most important high streets on the Anatolian side of Istanbul, Turkey. It runs approximately 14 km (8.7 mi) from Maltepe in the east to Kadıköy in the west, almost paralleling the coastline of the Sea of Marmara. The most important part of the street runs 6 km (3.7 mi) from Bostancı to Kızıltoprak within the district of Kadıköy. Bağdat Avenue is usually seen as the counterpart of Istiklal Avenue on the European side of the city in terms of its importance and glamour although it lacks the fine heritage of historic buildings to be found on Istiklal Avenue with almost all its architecture modern.