Kahanism (Hebrew: כהניזם) is a religious Zionist ideology based on the views of Rabbi Meir Kahane, founder of the Jewish Defense League and the Kach party in Israel. Kahane held the view that most Arabs living in Israel are the enemies of Jews and Israel itself, and believed that a Jewish theocratic state, where non-Jews have no voting rights, should be created.

The Kach party has been banned by the Israeli government. In 2004, the U.S. State Department designated it a Foreign Terrorist Organization. In 2022, it was removed from the U.S. terror blacklist due to "insufficient evidence" of the group's ongoing activity, but it remains a Specially Designated Global Terrorist entity.

The Kahanist Otzma Yehudit party won six seats in the 2022 election and is a member of the Israeli government, though it left between 21 January and 19 March 2025 because the government had agreed to a ceasefire in the Gaza war during that time. The party, and the Kahanist movement as a whole, have been described as espousing Jewish fascism.

The Kach party saw electoral success in 1984, winning 26,000 votes, equivalent to one seat. Early polls after the election predicted that the Kach party would become the third-largest party, winning as many as 12 seats in the next election. In August 1985, the Kach party was barred from participating in elections. Some Kahanist groups, such as the Sicarii, began pursuing their political goals through violent means instead. On November 5, 1990, Meir Kahane was assassinated by El-Sayyid A. Nosair, who was associated with terror cells that eventually became al-Qaeda.

Kahane's assassination led to the splintering of the Kach party, with Binyamin Ze'ev Kahane leading Kahane Chai from Kfar Tapuach and Kach led by Baruch Marzel, who eventually became a member of Otzma Yehudit. In 1992 both groups were banned completely from participating in elections. In 1994, due to the Cave of the Patriarchs massacre committed by Baruch Goldstein, they were declared illegal terrorist organizations by the Israeli government. After the ban, Kahane Chai's leaders created an extraparliamentary advocacy group, "The Kahane Movement", which archived media content from Kahane online.

The next election where Kahanists received political representation was in 2009, with Michael Ben-Ari, who ran on the National Union ticket. Ben-Ari split from the National Union after the election, forming Otzma Yehudit. Otzma Yehudit failed to pass the electoral threshold in the 2013 Israeli election.

Kahanism gained no political legitimacy until the April 2019 Israeli election. As a result of the 2018–2022 Israeli political crisis, Prime Minister Benjamin Netanyahu attempted to gain seats by appealing to Kahanist voters by making a deal with the Jewish Home party to have them run on a joint list with Otzma Yehudit as the Union of Right-Wing Parties. The party received enough seats for Otzma Yehudit to be represented, but Ben Ari, who was supposed to represent the fifth slot on the Union of Right-Wing Parties list, was barred from running after the list was submitted. Otzma Yehudit eventually achieved parliamentary representation in 2021, when Itamar Ben-Gvir won a seat as part of a joint list with the Religious Zionist Party.

Otzma Yehudit won six seats in the 2022 Israeli legislative election, forming what has been called the most right-wing government in Israeli history. In November 2022, after a memorial event for Kahane attended by Ben-Gvir, the U.S. State Department hosted a press briefing, saying, "Celebrating the legacy of a terrorist organization is abhorrent. There is no other word for it. It is abhorrent." The party left the coalition on 21 January 2025 because the government had agreed to a ceasefire in the Gaza war. That ceasefire collapsed on 18 March, and the party rejoined the government the next day.