The Islamic Jihad Movement in Palestine (Arabic: حركة الجهاد الإسلامي في فلسطين, Ḥarakat al-Jihād al-Islāmi fi Filastīn), commonly known simply as Palestinian Islamic Jihad (PIJ), is an Islamist Palestinian paramilitary organization formed in 1981.

PIJ formed as an offshoot of the Muslim Brotherhood and was influenced ideologically in its formation by the Islamic Revolution in Iran. It is a member of the Alliance of Palestinian Forces, which rejects the Oslo Accords and whose objective is the establishment of a sovereign Islamic Palestinian state. It calls for the military destruction of Israel and rejects a two-state solution. The organization's financial backing has historically come mainly from Syria and Hezbollah. Since 2014, PIJ has seen its power steadily increase with the backing of funds from Iran. PIJ has notably participated in the ongoing Gaza war (2023–present), fighting alongside Hamas and other allied Palestinian factions.

The armed wing of PIJ is Al-Quds Brigades (also known as "Saraya"), also formed in 1981, which is active in the West Bank and the Gaza Strip, with its main strongholds in the West Bank being the cities of Hebron and Jenin. Its operations have included suicide bombings, attacks on Israeli civilians, as well as the firing of rockets into Israel, targeting civilians. It has been deemed a terrorist organization by several countries.

PIJ was formally established in Gaza in 1981 by two Palestinian activists: Fathi abd al-Aziz Shaqaqi, a Rafah-based physician, and Shaykh Abd al-Aziz Awda, an Islamic preacher from the Jabaliyya refugee camp, as well as Ramadan Shalah, Bashir Moussa, and three other Palestinian radicals. Based in Egypt, Shaqaqi and Awda were originally members of the Muslim Brotherhood. Their views on the destruction of Israel led them in 1979 to establish Islamic Jihad-Shaqaqi Faction, a branch of the Egyptian Islamic Jihad. and conducted operations out of Egypt. The Shaqaqi Faction was expelled from Egypt in 1981, following the assassination of Anwar Sadat, the 3rd president of Egypt, by the Egyptian Islamic Jihad. Shaqaqi and Awda returned to Gaza where they formally established PIJ, from where it continued its operations.

The aim of the organization was the establishment of a sovereign Islamic Palestinian state within the geographic borders of pre-1948 Mandatory Palestine. Completely rejecting the political process, the organization professes that its goals can only be achieved through military means.

PIJ began its armed operations against Israel in 1984. In 1988, its leaders were exiled by Israel to Lebanon. While in Lebanon, the group received training, support and other backing from Hezbollah and its backers in Iran, and developed a close relationship with the organization. In 1990, the headquarters of PIJ moved to the Syrian capital, Damascus, where it continues to be based, with offices in Beirut, Tehran, and Khartoum.

PIJ masterminded several suicide attacks in Israel, and is considered by Israel the most extreme organization in its operational methods and commitment to the destruction of Israel. By 1995 PIJ was, according to Robert Fisk, "perhaps the fiercest of all Israel's modern-day enemies." There was a subsequent crackdown on the PIJ by Israel and the Palestinian National Authority which led to a significant weakening of the organization.

On 20 February 2003, University of South Florida computer engineering professor Sami Al-Arian was arrested after being indicted on a terrorism-related charge. U.S. attorney general John Ashcroft alleged at a press conference that Al-Arian was the North American head of the Palestinian Islamic Jihad. On 6 December 2006, Sami Al-Arian was sentenced to 57 months in prison, pursuant to a plea bargain. In November 2006 he was found guilty of civil contempt for refusing to testify before a federal grand jury and served 21 months in prison on that conviction. On 27 June 2014, the US Federal Government dropped all charges against Al-Arian.