A gendarmerie or gendarmery (/dʒɛnˈdɑːrməri/ or /ʒɑːnˈdɑːrməri/) is a military component with jurisdiction in civil law enforcement. The term "gendarmerie" is derived from the medieval French expression gens d'armes, which translates to "armed men". In France and most Francophone nations, the gendarmerie is the branch of the armed forces responsible for internal security during wartime. This concept was introduced to several other Western European countries during the Napoleonic conquests. In the mid twentieth century, a number of former French mandates or colonial possessions such as Syria and the Republic of the Congo adopted a gendarmerie after independence.
The growth and expansion of gendarmerie units worldwide has been linked to an increasing reluctance by some governments to use military units typically entrusted with external defense for combating internal threats. A somewhat related phenomenon has been the formation of paramilitary units which fall under the authority of civilian police agencies. Since these are not strictly military forces, however, they are not considered gendarmerie.
Some of the more prominent modern gendarmerie organizations include the French National Gendarmerie, Italian Carabinieri, and Spanish Civil Guard.