The Free French Naval Forces (French: Forces Navales Françaises Libres, or FNFL) were the naval arm of the Free French Forces during the Second World War. They were commanded by Admiral Émile Muselier.

In the wake of the Armistice and the Appeal of 18 June, Charles de Gaulle founded the Free French Forces (Forces Françaises Libres, or FFL), including a naval arm, the "Free French Naval Forces" (Les Forces Navales Françaises Libres, or FNFL). On 24 June 1940, de Gaulle made a separate call specifically to servicemen overseas to join him, and two days later the submarine Narval entered Malta and pledged its allegiance to the FFL. On 30 June, De Gaulle was joined by Vice-Admiral Émile Muselier, who had come from Gibraltar by flying boat. Muselier was the only flag officer of the French Navy to answer the call of De Gaulle.

The French fleet was widely dispersed. Some vessels were in port in France; others had escaped from France to British controlled ports, mainly in Britain itself or Alexandria in Egypt. At the first stage of Operation Catapult, the ships in the British ports of Plymouth and Portsmouth were simply boarded on the night of 3 July 1940. The then-largest submarine in the world, Surcouf, which had sought refuge in Portsmouth in June 1940 following the German invasion of France, resisted the British operation. In capturing the submarine, two British officers and one French sailor were killed. Other ships were the two obsolete battleships Paris and Courbet, the destroyers Le Triomphant and Léopard, eight torpedo boats, five submarines (Minerve, Junon) and a number of other smaller vessels. 3,600 sailors operating 50 ships around the world joined with the Royal Navy and formed the nucleus of the Free French Naval Forces France's surrender found her only aircraft carrier, Béarn, en route from the United States loaded with a precious cargo of American fighter and bomber aircraft. Unwilling to return to occupied France, but likewise reluctant to join de Gaulle, Béarn instead sought harbour in Martinique, her crew showing little inclination to side with the British in their continued fight against the Nazis. Already obsolete at the start of the war, she would remain in Martinique for the next four years, her aircraft rusting in the tropical climate.

As soon as the summer 1940, the submarines Minerve and Junon, as well as four avisos, departed from Plymouth. Towards the end of 1940, the destroyers Le Triomphant and Léopard followed. Le Triomphant sailed for New Caledonia and spent the rest of the war based there and in Australia. The ship saw action in both the Pacific and Indian Oceans.

Civilian vessels and crew also rallied to de Gaulle, starting with four cargo ships in Gibraltar - they would be the beginning of the merchant fleet of the FNFL.

To distinguish the FNFL from the Vichist forces, Vice-Admiral Émile Muselier created the bow flag displaying the French colours with a red Cross of Lorraine, and a cocarde also featuring the Cross of Lorraine for aircraft of the Free French Naval Air Service (Aéronavale Française Libre) and the Free French Air Force (Forces Aériennes Françaises Libres).

A number of ships were leased from the British to compensate for the lack of warships in the FNFL, among them, the Hunt-class destroyer La Combattante and the Flower-class corvette Aconit.

The FNFL suffered their first loss when the patrol boat Poulmic hit a mine and sank on 7 November 1940 off Plymouth.