Steenwerck (French pronunciation: [stɛ̃vɛʁk]; Dutch: Steenwerk) is a commune, in French Flanders, in the Nord department in northern France. It is located about 25 km (16 mi) north of Lille. People from Steenwerck are known as Steenwerckois.

It is home to Steenwerck's 100 km à pied race event, which mainly features a 100 km (62 mi) marathon, although most local residents prefer to merely walk one lap (roughly 22 kilometres (14 mi)).

Steenwerck also has its own festival giant, as is the tradition in the Nord Department, which is named Totor and is one of the tallest, measuring 5.70 m (18.7 ft).

Other places of interest include the Museum of Rural Life as well as three Commonwealth war cemeteries, and a German war cemetery, of the First World War.

Steenwerck was created by the Franks. The first mention in the 12th century – in 1160 with the invasion by La Becque, from Saint-Jans-Cappel.

Commerce was originally started by the town's founder, la Becque, who built canals with locks right up to Lys. The local weavers were able to deliver their bolts of cloth to the port situated in the town centre from where they would be sent on to the clothes manufacturing town of Armentièrs. The boats used were called martsheps, that is, 'market boats', which were flat bottomed boats. It was by using these boats that local farmers were able to deliver their produce to the neighbouring towns. Boats of this type were used right up until the middle of the 19th century.

Through the course of history, several variations have appeared: for the period when Middle Dutch was spoken (1150 - 1550) one would see:

Then in various documents, the name became Stewerc.