Nord-Pas-de-Calais (French pronunciation: [nɔʁ pɑ d(ə) kalɛ] ^ⓘ; Picard: Nord-Pas-Calés; West Flemish: Nôord-Nauw van Kales) was a former administrative region of France. Since 1 January 2016, it has been part of the new region Hauts-de-France. It consisted of the departments of Nord and Pas-de-Calais. Nord-Pas-de-Calais bordered the English Channel (west), the North Sea (northwest), Belgium (north and east), and Picardy (south). Until the 17th century, the history of the North was largely shared with the history of Belgium (the Celtic Belgians during Antiquity were a multitude of Celtic peoples from the north of Gaul), that of a land that "for almost a thousand years served as a battlefield for all of Europe."

The majority of the region was once part of the historical Southern Netherlands, but gradually became part of France between 1477 and 1678, particularly during the reign of King Louis XIV. The historical French provinces that preceded Nord-Pas-de-Calais are Artois, French Flanders, French Hainaut, and (partially) Picardy (part of Hainaut and Flanders is in the Kingdom of Belgium). These provincial designations are still frequently used by the inhabitants. The former administrative region was created in 1956 under the name "Nord" and maintained that name until 1972, when "Pas-de-Calais" was added. This remained unchanged until its dissolution in 2016.

With a population density of 330.8 people per km² on just over 12,414 km², it was a densely populated region inhabited by 4.1 million people, 7% of France's total population, making it the fourth most populous region in the country, 83% of whom live in urban communities. Its administrative centre and largest city is Lille. The second largest city is Calais, which serves as a major continental economic/transportation hub with Dover of Great Britain 42 kilometres (26 mi) away; this makes Nord-Pas-de-Calais the closest continental European connection to the island of Great Britain. Other major towns include Valenciennes, Lens, Douai, Béthune, Dunkirk, Maubeuge, Boulogne, Arras, Cambrai, and Saint-Omer. The region is featured in numerous films, including Bienvenue chez les Ch'tis.

Nord-Pas-de-Calais combines the names of the constituent departments of Nord (literally 'North', the northernmost department of France) and Pas-de-Calais ('Strait of Calais', the French name of the Strait of Dover). The regional council, however, spells the name Nord-Pas-de-Calais.

The northern part of the region was historically a part of the County of Flanders, with Lille as its capital. Those who wish to highlight the historical links the region has with Belgium and the Netherlands prefer to call this region the French Low Countries, which also means French Netherlands in French (French: Pays-Bas français; Dutch: Franse Nederlanden or Franse Lage Landen). Other alternative names are Région Flandre(s)-Artois, Hauts-de-France, ('Upper France') and Picardie-du-Nord ('Northern Picardy').

Inhabited since prehistoric times, the Nord-Pas-de-Calais region has always been a strategic (and hence a highly fought-over) region in Europe. French President Charles de Gaulle, who was born in Lille, called the region a "fatal avenue" through which invading armies repeatedly passed. Over the centuries, it was conquered in turn by the Celtic Belgae, the Romans, the Germanic Franks, England, the Spanish and Austrian Netherlands, and the Dutch Republic. After the final French annexation in the early 18th century, much of the region was again occupied by Germany during the First and Second World Wars.

During the 4th and 5th centuries, the Roman practice of co-opting Germanic tribes to provide military and defense services along the route from Boulogne to Cologne created a Germanic–Romance linguistic border in the region that persisted until the 8th century. By the 9th century, most inhabitants north of Lille spoke a dialect of Middle Dutch, while the inhabitants to the south spoke a variety of Romance dialects. This linguistic border is still evident today in the place names of the region. Beginning in the 9th century, the linguistic border began a steady move to the north and the east. By the end of the 13th century, the linguistic border had shifted to the river Lys in the south and Cap Gris-Nez in the west.

During the Middle Ages, the Pas-de-Calais department comprised the County of Boulogne and the County of Artois, while the Nord department was mostly made up of the southern portions of the County of Flanders and the County of Hainaut. Boulogne, Artois, and Flanders were fiefs of the French crown, while Hainaut and (after 1493) Flanders were within the Holy Roman Empire. Calais was an English possession from 1347 to 1558, when it was recovered by the French throne. In the 15th century, all of the territories, except Calais, were united under the rule of the Dukes of Burgundy, along with other territories in northern France and areas in what is now Belgium, Luxembourg, and the Netherlands. With the death of the Burgundian duke Charles the Bold in 1477, the Boulonnais and Artois were seized by the French crown, while Flanders and Hainaut were inherited by Charles's daughter Marie. Shortly thereafter, in 1492, Artois was ceded back to Marie's son Philip the Handsome, as part of an attempt to keep Philip's father, Emperor Maximilian I, neutral in French King Charles VIII's prospective invasion of Italy.