Reus (Catalan pronunciation: [ˈrɛws]) is the capital of Baix Camp, in Camp de Tarragona, Catalonia, Spain. It has a population of 109,930 (register office, 2024) .

The area has long been an important producer of wines and spirits, and gained continental significance during the time of the Phylloxera plague. Currently it is known for its commercial activity, as a center for rock climbing, and as the birthplace of architect Antoni Gaudí.

The origin of the name Reus is a subject of debate. One of the theories is that Reus comes from the Latin word used to describe convict prisoners (reus), and as such, it would be a Roman penitentiary. Currently, the most accepted theory is that the name has Celtic roots, from the root red that originated the name redis (or reddis), that approximately meaning 'place on the way' or 'crossroads settlement', or said alternatively, an inhabited place in a cross-road.

Around 1150 Robert d'Aguiló repopulated the region of Reus, after receiving it on 3 June 1154. On 5 June 1154 the archbishop of Tarragona gave two-thirds of Reus to Bertran de Castellet, as a castellan, with the order to build a church. On 29 June 1159, the distribution of income from ecclesiastical goods, the third of its Reus parish of Santa Maria was awarded to the camerlengo, starting the duplicity of governing the town. At this time the city was known as Redis or Reddis. The castellan Bernat de Bell-lloc granted Reus the title of town on 3 August 1183, giving the ownership of houses and gardens, establishing a census to fund farmland but reserved legal authority, but recognizing its vassalage towards the archbishopric of Tarragona. On 2 June 1186 the camerlengo Joan de Santboi confirmed the rights given by the castellan Bernard de Bell-lloc.

In 1305 Reus revolted against the Archbishop Rodrigo Tello, who wanted the citizens of Reus to pay for rebuilding the walls of Tarragona. In 1309 the king of Aragon gave Reus the right to hold a market on Mondays. The dynasty of Bell-lloc castellans became extinct in 1327 and then Bernard de Cabrera became the new castellan, but in 1335 the castellan was sold to Pere Mulet, who lost it on 1345. Pere Mulet heirs sold their rights to Bernat d'Olzinelles in 1349. The camerlengo Pere Roger de Belfort disputed domain to the Archbishop López de Ayerbe, who sent an army that decimated the town. A second attack was repulsed. A third attack was led by military occupation of the town and Reus was sacked. The camerlengo Pere Roger de Belfort, nephew of Pope Clement VI, who was living in Avignon with his uncle, persuaded the Pope to call the archbishop of Tarragona and the Pope received a commitment for peace. Pere Roger de Belfort gave the roses off his coat to coat of arms of the town and he later became Pope Gregory XI, he retained the title as a camerlengo of Reus, so the coat of arms was crowned and adorned with, a papal tiara and the keys of St. Peter.

At the beginning of the Catalan Revolt war the town had 1200 houses, but reduced to 800 by the end of the war. On 16 December 1640 was declared an enemy of the fatherland by the Parliament and confiscated the goods of the inhabitants, as a response to the inactive participation in the war. In 1641 it was occupied by the French general La Mothe.

Reus was loyal to Philip V until 1705, but this year, under the direction of Joan Nebot, revolted in favor of the Archduke Charles. On 3 July 1706 the Archduke Charles came to the town. In 1707 fell shortly to the Bourbons, but in 1709 Reus surrendered to the Spanish and French Bourbons. In 1710 Reus returned again to the field of Archduke Charles. On 5 June 1712 the wife of the Archduke, Elisabeth Christine, gave the title of imperial city to Reus. In 1713 Reus was occupied finally by the Bourbon.

In the eighteenth century Reus had extreme growth and became the second city of the principality of Catalonia. The walls were completely demolished in 1766. The town developed the textile trade and the liquor trade. In this last contribution was the first center, the others were London and Paris. From this time it's the popular sentence "Reus, Paris and London", because Reus was one of the centers of the liquor marquet. The construction of a canal between Reus and Salou, proposed by Pere Sunyer was granted in 1805, but it was stopped because of the French War. At this time Reus had consulates in the United States, Liguria, England, Holland, Sweden, Ragusa, Denmark, Sicily, the Papal States, France, Portugal, Naples and Prussia.