Bailleul (French pronunciation: [bajœl] ^ⓘ; Belle in Dutch) is a commune in the Nord department in northern France. It is located in French Flanders, 3 km (2 mi) from the Belgian border and 26 km (16 mi) northwest of Lille.

Bailleul is the birthplace of French filmmaker Bruno Dumont and served as the setting for his first two feature films. This area is also a setting in the Timothy Findley book The Wars.

The city hall and belfry of Bailleul was inscribed on the UNESCO World Heritage List in 2005 as part of the Belfries of Belgium and France site, in recognition of their importance in the rise of municipal power in Europe.

The Jardin des Plantes Sauvages du Conservatoire botanique national de Bailleul is a botanical garden of protected plants. Over 850 species of native plants are found in the garden.

In 1526, Flanders fell to the Spanish Netherlands by the Treaty of Madrid. Under the reign of Philip II, the first religious problems arose between Flanders and Spain.

In the 17th century, Flanders was a permanent battlefield. Louis XIV reconquered Flanders. As a result, Bailleul reverted to France in 1678.

With the Treaty of Utrecht, Flanders and with it Bailleul fell to Austria in 1713, before both finally passed to France in 1745 after the Battle of Fontenoy and the Treaty of Aachen. Numerous fires marked the history of the city.

From the 17th to the 19th century, the bobbin lace craft developed in Bailleul. (La Maison de la Dentelle bobbin lace museum), a craft for which the town is still known far beyond its borders.