The Temple at Didyma (modern Didim) was a major sanctuary of Apollo on the Eastern Aegean Coast. It was around 20 km from Miletus at the southern end of its Sacred Way.

According to legend, the temple was founded even before Greek settlers arrived in the area. Construction of the second temple began around the middle of the 6th century BCE though it was destroyed by the Persians in the following century. It was in ruins, so we are told, until Alexander the Great began to rebuild the temple. It was a massive structure, even larger than the Temple of Artemis in Ephesus one of the Seven Wonders of the World. It had a total of 120 Ionic columns which were almost 20 m tall. It measured over 110 meters by 50 meters. While work continued throughout antiquity, the temple was never finished. The Romans held the Oracle of Apollo at the Temple of Didyma in high regard, during which time its importance even surpassed the famous Oracle of Apollo at Delphi.

The temple, though, was closed in the late 4th century by Emperor Theodosius I when he made Christianity the official religion of the Roman Empire. In Late Antiquity, a basilica was built in its inner sanctuary which served as the seat of the bishop. A smaller church was later built in the temple ruins after an earthquake destroyed this basilica. While partial excavations began in the 19th century the site was not fully excavated until the early 20th century. During this time, the remains of the basilica were demolished in order to present the Classical phase of the temple.