Beypazarı (Ancient Greek: Λαγανια, Lagania) is a town and district of Ankara Province in the Central Anatolia region of Turkey, approximately 100 km west of the city of Ankara. According to 2000 census, population of the district is 46,493 of which 35,775 live in the town of Beypazarı. The district covers an area of 1,814 km² (700 sq mi), and the average elevation in the center is 675 m (2,215 ft). The district contains three other small towns (Karaşar, Uruş, Kırbaşı) and 64 villages. It used to be an important city in Asia Minor in ancient times.

The name Beypazarı means The Bey's market in Turkish, as in the Ottoman period this was an important military base and the cavalry stationed here were an important element of the local economy.

The area has a long history of occupation by Hittites, Phrygians, Ancient Romans, Byzantines, Seljuk Turks and the Ottoman Empire.

Originally a stop on a trade route connecting Istanbul to Baghdad, Beypazarı was known as Lagania (Greek: Λαγάνια), meaning rocky peak in the Luwian language during the Roman and Byzantine times, and the town was a regional administrative center.