The al-Aqsa Martyrs' Brigades (Arabic: كتائب شهداء الأقصى) are a Palestinian militant group closely linked to the Fatah political party and one of the most active forces in the al-Aqsa Intifada. The group targets civilians and is thus a designated terrorist organization according to Israel, the U.S * and the European Union *. Named after the al-Aqsa Mosque, an Islamic holy site, the group's membership is primarily drawn from the ranks of Tanzim, a militant youth group within al-Fatah. Following the death of Yasser Arafat on November 11, 2004, the group announced that they will sign their attacks in the name Brigades of Shahid Yasser Arafat.

The group initially vowed to target only Israeli soldiers and settlers in the West Bank and Gaza Strip and to carry out guerrilla warfare against the Israeli military, though from early 2002 it began a series of attacks against civilians in Israeli cities. In March 2002, after a al-Aqsa Brigade suicide bombing in Jerusalem, the group was designated as a foreign terrorist organization by the United States Department of State although they haven't carried out attacks on American soil.

At that time, many Palestinian sources stated that the group was not officially backed by Arafat and Fatah, though brigade members tend also to be members of Fatah, Arafat's political faction, and Maslama Thabet, one of the group's leaders, told USA Today that "We receive our instructions from Fatah. Our commander is Yasser Arafat himself." In June 2004, Palestinian National Authority Prime Minister Mahmoud Abbas openly stated that the Brigades were part of Fatah. Israel charges that neither Fatah nor the Palestinian National Authority have made any attempt to prevent their attacks. On December 18, 2003, Fatah decided to ask the leaders of the al-Aqsa Martyr's Brigades to join the Fatah Council, recognizing it officially as part of the organization. Israel has published documents found in Arafat's compound to support their claim that Arafat knowingly sponsored al-Aqsa attacks.

In October 2005, when Iranian President Mahmoud Ahmadinejad was falsely quoted as urging Arabs to "wipe Israel off the map," the Brigades issued a statement saying that they "hold identification with and overall support of the position and declaration of the Iranian president, who called with all honesty to wipe Israel off the map of the world" *.