The National Gendarmerie (French: Gendarmerie nationale [ʒɑ̃daʁməʁi nɑsjɔnal]) is one of two national law enforcement forces of France, along with the National Police. The Gendarmerie is a branch of the French Armed Forces placed under the jurisdiction of the Ministry of the Interior, with additional duties from the Ministry of Armed Forces. Its responsibilities include policing smaller towns, suburbs and rural areas, crowd and riot control, and criminal investigation, including cybercrime. By contrast, the National Police is a civilian law enforcement agency that is in charge of policing cities and larger towns. Because of its military status, the Gendarmerie also fulfills a range of military and defence missions. The Gendarmerie has a strength of around 102,269 people (as of 2018).

The Gendarmerie is the heir of the Maréchaussée, the oldest police force in France, dating back to the Middle Ages. The Gendarmerie has influenced the culture and traditions of gendarmerie forces around the world, especially in independent countries from the former French colonial empire.

The Gendarmerie is the direct descendant of the Maréchaussée ("Marshalcy") of the ancien regime. The Maréchaussée lasted from medieval times until the French Revolution.

During the Middle Ages, there were two Grand Officers of the Kingdom of France with police responsibilities: The Marshal of France and the Constable of France. The military policing responsibilities of the Marshal of France were delegated to the Marshal's provost, whose force was known as the Marshalcy because its authority ultimately derived from the Marshal. The Marshalcy dates back to the Hundred Years' War, with some historians tracing it back to the early 12th century.

The second organisation, the Constabulary (Connétablie), was under the command of the Constable of France. The constabulary was regularised as a military body in 1337.

In 1415 the Maréchaussée fought in the Battle of Agincourt and their commander, the Prévôt des Maréchaux (Provost of the Marshals), Gallois de Fougières, was killed in battle. This history was rediscovered in 1934, and Gallois de Fougières was then officially recorded as the first known gendarme to have died in the line of duty. His remains are now buried under the monument to the gendarmerie in Versailles.

Under King Francis I (r. 1515–1547), the Maréchaussée was merged with the Constabulary. The resulting force was also known as the Maréchaussée, or, formally, the Constabulary and Marshalcy of France (connétablie et maréchaussée de France). Unlike the former constabulary, the new Maréchaussée was not a fully militarized force.

In 1720, the Maréchaussée was officially attached to the Household of the King (Maison du Roi), together with the gendarmerie of the time, which was not a police force at all, but a royal guard. During the eighteenth century, the marshalcy developed in two distinct areas: increasing numbers of Marshalcy Companies (compagnies de marechaussée), dispersed into small detachments, were stationed around the French countryside to maintain law and order, while specialist units provided security for royal and strategic sites such as palaces and the mint (e.g., the garde de la prévôté de l'hôtel du roi and the prévôté des monnaies de Paris.)