The Israel Security Agency, better known by the acronyms Shabak or Shin Bet, is Israel's internal security and counterintelligence service. Its motto is "Magen v'lo Yera'eh" (Hebrew: מָגֵן וְלֹא יֵרָאֶה, lit. 'the unseen shield'). The Shin Bet's headquarters are located in northwest Tel Aviv, north of Yarkon Park.

It is one of three principal organizations of the Israeli Intelligence Community, alongside Aman (military intelligence) and Mossad (foreign intelligence service).

Shabak is believed to have three operational wings:

Although a security agency, it is not a part of the Israeli Ministry of Defense, and its chief answers directly to the prime minister of Israel.

Shabak's duties are safeguarding state security, exposing terrorist rings, interrogating terror suspects, providing intelligence for counter-terrorism operations in the West Bank and the Gaza Strip, counter-espionage, personal protection of senior public officials, securing important infrastructure and government buildings, and safeguarding Israeli airlines and overseas embassies.

With the Israeli declaration of independence in 1948, the Shabak was founded as a branch of the Israel Defense Forces and was initially headed by Isser Harel (the father of Israeli Intelligence, who later headed the Mossad). Responsibility for Shabak activity was later moved from the IDF to the office of the prime minister. During the 1948 Arab–Israeli war, Shabak's responsibilities included only internal security affairs. In February 1949 (a short while before the end of the war), its responsibilities were extended to counter-espionage.

One of the Shabak's leading successes was obtaining a copy of the secret speech made by Nikita Khrushchev in 1956, in which he denounced Stalin. A Polish edition of the speech was provided to the Israeli embassy in Warsaw by the boyfriend of the secretary of a Polish communist official. The Shabak's Polish liaison officer conveyed the copy to Israel. The Israeli government then decided to share the information with the United States, which published it with Israeli approval. On the other hand, a study published in 2013 by Matitiahu Mayzel casts doubt on the story, arguing that the speech was not secret and that it was conveyed to the West by multiple sources, including Soviet political and intelligence agencies.

A notable achievement in counter-espionage was the 1961 capture of Israel Beer, who was revealed to be a Soviet spy. Beer was a lieutenant colonel in the reserves, a senior security commentator and close friend of Ben-Gurion and reached high Israeli circles. Beer was tried and sentenced to ten years in prison (later extended by the Supreme Court to fifteen years, following his appeal), where he died. A year before, Kurt Sitte, a Christian German from the Sudetenland and a professor in the Technion, was revealed as a Czechoslovakian spy.