Estaires (French pronunciation: [etɛʁ]; West Flemish: Stegers) is a commune in the Nord department of the Hauts-de-France region in northern France.

It was positioned strategically on the road linking Castellum Menapiorum (Cassel) to the capital of the Atrebates peoples, Nemetacum Atrebatum (Arras), at the narrowest crossing of the Lys.

It was part of the County of Flanders from its inception as was most of the Lys plain and was a lordship manor.

The Lys formed a language border; to the north they spoke Flemish and to the south Picard (Romance Flanders).

Flanders was strongly Catholic, but advent of Lutheran thought in the sixteenth century led to religious unrest.

In Estaires, on the day of Corpus Christi, the Geuzen mockingly processed with a donkey under a canopy in place of a priest.

There are virtually no buildings dating from before 1918; the town was completely destroyed by German bombing on 9 and 10 April 1918, then by the allies until October 1918.