Cayenne (; French pronunciation: [kajɛn] ; Guianese Creole French: Kayenn) is the prefecture and capital city of French Guiana, an overseas region and department of France located in South America. The city stands on a former island at the mouth of the Cayenne River on the Atlantic coast. The city's motto is "fert aurum industria", which means "work brings wealth". Cayenne is the largest Francophone city of the South American continent.

In the 2021 census, there were 151,103 inhabitants in the metropolitan area of Cayenne (as defined by INSEE), 63,468 of whom lived in the city (commune) of Cayenne proper.