Rethel (French: [ʁətɛl] ⓘ) is a commune in the Ardennes department in northern France.

The parents of St. Arnulf of Metz were said to have given all they owned in villa Reistete (in the city of Rethel) to St. Remigius, bishop of Reims, so that their prayers for a child would be answered.

During the Franco-Spanish War it was captured by Spanish forces under Louis de Bourbon, Prince of Condé on 30 October 1652 after a four-year siege, but was retaken by the French in July 1653.

Jean-Baptiste Reberotte-Labesse cared for the soldiers who were ill. Cholera epidemics occurred in 1832 and 1849, while typhoid fever ravaged the city in 1839, with an average of thirty deaths a day.

During World War II Rethel was the site of heavy combat from May to June 1940 during the Battle of France.