Alexandroupolis existed in antiquity with the ancient name Sali, which was founded by Maronites. The modern city of Alexandroupolis was founded as a small fishing village in the early 19th century under the Ottoman Empire, by fishermen from Ainos and the villages of Makri and Maroneia. It became known as Dedeagats.

From the first days of the city's capture (May 14, 1920), the local authorities as well as the Metropolitan, decided to rename the city from Dedeağaç to Neapoli ("new city"), as it was the newest Greek city. In 1920, King Alexander I of Greece visited the city, and the local authorities renamed the city Alexandroupoli ("city of Alexander") in his honor, with the approval of the central government.