Aspendos was an ancient city in Pamphylia, Asia Minor, located about 40 km east of the modern city of Antalya, Turkey. It was situated on the Eurymedon River about 16 km inland from the Mediterranean Sea; it shared a border with, and was hostile to, Side. According to later tradition, the (originally non-Greek) city was founded around 1000 BC by Greeks who may have come from Argos. The wide range of its coinage throughout the ancient world indicates that, in the 5th century BC, Aspendos had become the most important city in Pamphylia. At that time the Eurymedon River was navigable as far as Aspendos, and the city derived great wealth from a trade in salt, oil and wool.

In 190 BC the city surrendered to the Romans, who later pillaged its artistic treasures. Toward the end of the Roman period the city began a decline that continued throughout Byzantine times. Aspendos is known for having the best-preserved theatre of antiquity. With a diameter of 96 metres (315 ft), the theatre provided seating for 7,000.
The theatre was built in 155 by the Greek architect Zenon, a native of the city. It was periodically repaired by the Seljuqs, who used it as a caravansaray, and in the 13th century the stage building was converted into a palace by the Seljuqs of Rum.

In order to keep with Hellenistic traditions, a small part of the theatre was built so that it leaned against the hill where the Citadel (Acropolis) stood, while the remainder was built on vaulted arches. The high stage served to seemingly isolate the audience from the rest of the world. The ‘scaenae frons’ or backdrop, has remained intact. The 8.1 metre (27 ft) sloping reflective wooden ceiling over the stage has been lost over time. Post holes for 58 masts are found in the upper level of the theatre. These masts supported a velarium or awning that could be pulled over the audience to provide shade.

The Aspendos International Opera and Ballet Festival offers an annual season of productions in the theatre in the spring and early summer.

Nearby stand the remains of a basilica, agora, nymphaeum and 15 kilometres (9.3 mi) of a Roman aqueduct. The Roman Eurymedon Bridge, reconstructed in the 13th century, is also in the vicinity.