The Derby du Nord (French pronunciation: [døbi du nɔʁ], Northern Derby) is a football match contested between French clubs RC Lens and Lille OSC, two of region's most successful clubs. The derby has the name despite Lille being the only club of the two situated in the department of Nord. Lens are situated in the western department of Pas-de-Calais. The name can also refer to matches involving Lille and Valenciennes as both clubs are located within Nord, however, the match historically refers to matches involving Lille and Lens. As a result, the Lille–Valenciennes match is sometimes referred to as Le Petit Derby du Nord.
The two clubs first met in 1937 when Lille were playing under the Olympique Lillois emblem. Due to each club's close proximity towards each other being separated by only 40 kilometres (25 mi) and sociological differences between each club's supporters, a fierce rivalry developed. The Derby du Nord is underpinned by social and economic differences, since the city of Lens is known as an old, working-class, industrial city and Lille as a middle-class, modern, internationally-oriented one. Nowadays the matches, which can spark intense feelings on both sides, have gained prominence as they may determine berths in continental competitions.