Valenciennes (/ˌvælɒ̃ˈsjɛn/, also UK: /ˌvælənsiˈɛn/, US: /-nz, vəˌlɛnsiˈɛn(z)/, French: [valɑ̃sjɛn] ^ⓘ; also Dutch: Valencijn; Picard: Valincyinnes or Valinciennes; Latin: Valentianae) is a commune in the Nord department of Upper France.

It lies on the Scheldt (French: Escaut) river. Although the city and region experienced a steady population decline between 1975 and 1990, it has since rebounded.

In 923, it passed to the Duchy of Lower Lotharingia dependent on the Holy Roman Empire. Once the Empire of the Franks was established, the city began to develop, though the archaeological record has still not revealed all it has to reveal about this period.^{[citation needed]}

In 1259, Valenciennes was the site of a General Chapter of the Dominican Order at which Thomas Aquinas together with masters Bonushomo Britto, Florentius, Albert, and Peter took part in establishing a ratio studiorum or program of studies for the Dominican Order that featured the study of philosophy as an innovation for those not sufficiently trained to study theology. This innovation initiated the tradition of Dominican scholastic philosophy put into practice, for example, in 1265 at the Order's studium provinciale at the convent of Santa Sabina in Rome, out of which would develop the Pontifical University of Saint Thomas Aquinas, Angelicum.

In 1524, Charles V, Holy Roman Emperor, arrived at Valenciennes, and – even when Henry II of France allied with him against the Protestants in 1552 – Valenciennes became (c. 1560) an early center of Calvinism and in 1562 was location of the first act of resistance against persecution of Protestants in the Spanish Netherlands. On the "Journée des Mals Brûlés" (Bad Burnings Day) in 1562, a mob freed some Protestants condemned to die at the stake. In the wave of iconoclastic attacks called the Beeldenstorm that swept the Habsburg Netherlands in the summer of 1566, the city was the furthest south to see such an attack on August 24, 1566. It was also one of the first to feel the hand of repression after the siege and fall of the city on March 23, 1567. One of the victims of that repression was Guido de Bres, the author of the Belgic Confession. Following the "révolte des gueux's victory at Brielle, the army of Louis of Nassau, one of the major commanders of the Dutch rebel forces and supported by the Huguenot leader Gaspard de Coligny, invaded the Spanish Netherlands with an army composed of German, English, Scottish and French soldiers, and took Valenciennes on 21 May 1572. However, Louis went on to Mons, and the Protestant garrison left behind offered only a feeble defence to the Duke of Alba, at the head of the bulk of the Spanish army, who recaptured Valenciennes in early June 1572, depriving Louis's French allies of one of their main bases.

The French army laid siege to the city in 1656 (Vauban participated in this siege without a command). Defending the city, Albert de Merode, marquis de Trélon was injured during a sortie on horseback, died as a result of his injuries and was buried in the Church of St. Paul (his tomb was found during the archaeological campaign in 1990).^{[citation needed]}

In 1677, the armies of Louis XIV of France (this time led by Vauban) captured the city and in 1678 the Treaty of Nijmegen gave the French control of Valenciennes (1678) and the surrounding southern part of Hainault, roughly cutting the former county in half.^{[citation needed]}

The city was besieged by the First Coalition against Revolutionary France in 1793.