Didymóteicho is a town located in the eastern part of the Evros Prefecture of Thrace, Greece.

It is the seat of the municipality and the province of the same name. It is located around 12 km from Turkey and the western banks of the Evros. It is the easternmost municipality on the mainland of Greece (in its town of Pythio). In the west, much of the land is mountainous and forested, while farmlands are located in the central and the northern part. It is on the railway line Thessaloniki-Istanbul and the Greek road 51 (Alexandroupoli - Orestiada - Edirne in Turkey and Svilengrad in Bulgaria). The town (pop. 8,799 in 2001) sits on a plain and located south east of Svilengrad, south of Edirne, Turkey and Orestiada, west of Uzunköprü, about 20 km north of Soufli and about 90 km north of Alexandroupoli. The Municipality of Didymóteicho has a land area of 354.134 km² and a population of 18,998 inhabitants. Its largest other towns are Lagós (pop. 1,403), Koufóvouno (958), Sofikó (926), Ellinochóri (756), and Karotí (723).

The area around the town was founded at neolithic times. It was an important Thracian and Hellenistic town. The town was sacked by the Romans in 204 BC. In the early 2nd century, the Roman emperor Trajan created a new city between the two hills surrounding the town and named it Plotinopolis after his wife Pompeia Plotina. The city would later be one of the most important town in Thrace, having her own assembly. Its remains are now known as the Kale, after the Turkish for "castle". In the 1980s, a solid gold bust of Trajan was found on the site of Plotinopoulis and is now in the museum at Komotini.