Shayetet 13 (Hebrew: שייטת 13, lit. 'Flotilla 13') is a naval commando unit of the Israeli Navy and one of the primary reconnaissance units of the Israel Defense Forces. Shayetet 13 specializes in sea-to-land incursions, counter-terrorism, sabotage, maritime intelligence gathering, maritime hostage rescue, and boarding. The unit is trained for sea, air and land actions. The unit has taken part in almost all of Israel's major wars, as well as other actions.

The unit is one of the most secretive in the Israeli military. The details of many missions and identities of active operatives are kept highly classified. The unit is respected as among the best of the world's special forces, and is compared to the US Navy SEALs and Britain's Special Boat Service. Unlike many other Israeli Special Forces Units which take men only for their 36-month mandatory service, volunteers for Shayetet 13 must agree to serve at least four and a half years.

Shayetet 13 is a veteran Israeli special forces unit. It was formed in 1949 by Yohai Ben-Nun with men drawn from the ranks of the Palyam, the naval branch of the Palmach, the elite fighting force of the Haganah, the ancestor of the Israel Defense Forces. The need for such a dedicated unit was a matter of debate during the early years of the IDF, and the unit subsequently suffered size and budget restrictions. Upon its foundation, the existence of Shayetet 13 was a state secret, and its members wore general Israeli Navy insignia rather than their own unique one.

Shayetet 13 commandos participated in the 1956 Suez Crisis. They performed several failed reconnaissance missions before the war and later participated in the land campaign as regular soldiers. A plan for Shayetet 13 commandos to capture an Egyptian Navy frigate was almost put into action. The plan was called off because the elite unit's soldiers were deemed too valuable to risk for low-priority targets.

In 1957, Shayetet 13 began to jointly train with the French Marine Commandos, and as a result, information about its existence began to leak. Two years later, the unit's soldiers were permitted to wear their distinctive bat insignia, and the existence of the unit was made public the year after that.

In the late 1950s, Shayetet 13 commandos carried out a series of reconnaissance missions to monitor the deliveries of Soviet gunboats to Syria and monitor Lebanon during the 1958 Lebanon crisis. On July 9, 1958, Shayetet 13 operatives infiltrated Beirut harbor in Operation Yovel. They were spotted and had to retreat, swimming back out to sea where an Israeli Navy torpedo boat picked them up and exchanged fire with a Lebanese patrol craft that intervened. The Israelis were able to retreat without any casualties. In 1962, it participated in a joint operation with the Golani Brigade against Syrian positions in the Golan Heights in retaliation for Syrian firing on Israeli fishermen. While the Golani force was successful, the Shayetet 13 force failed to complete its mission, a raid on a Syrian post in Kursi, and retreated without casualties after coming under fire. The fiasco became known as "Operation Rabbit".

In August 1966, the unit was given the mission of retrieving the wreckage of a Syrian Air Force MiG that had been shot down and crashed into the Sea of Galilee. Near the end of the operation, Syrian troops opened fire, and the salvage rope attached to the aircraft was dropped. The Syrians were later able to pick it up and drag their aircraft to safety.

During the 1967 Six-Day War, the unit was tasked with neutralizing enemy fleets. Shayetet 13 commandos infiltrated Port Said, but found no ships there, and during a raid into Alexandria, six divers were captured and taken prisoner, and released in January 1968. Several other missions also failed.