Coordinates: 49°22′54″N 3°19′25″E / 49.3817°N 3.3236°E / 49.3817; 3.3236

Soissons (French pronunciation: [swa.sɔ̃]) is a commune in the Aisne department in Picardy in northern France, located on the Aisne River, about 100 kilometres (62 mi) northeast of Paris. It is one of the most ancient towns of France, and is probably the ancient capital of the Suessiones. Soissons is also the see of an ancient Roman Catholic diocese, whose establishment dates from about 300.

Soissons enters written history under its Celtic name (as later borrowed in Latin), Noviodunum, meaning "new hillfort". At Roman contact, it was a town of the Suessiones, mentioned by Julius Caesar (B. G. ii. 12). Caesar (B.C. 57), after leaving the Axona (modern Aisne), entered the territory of the Suessiones, and making one day's long march, reached Noviodunum, which was surrounded by a high wall and a broad ditch. The place surrendered to Caesar.

From 457 to 486, under Aegidius and his son Syagrius, Noviodunum was the capital of the "Kingdom of Soissons", until it fell to the Frankish king Clovis I in the Battle of Soissons.