Abu Sayyaf (Arabic: جماعة أبو سياف‎; Jamāʿah Abū Sayyāf, ASG, Filipino: Grupong Abu Sayyaf) also known as al-Harakat al-Islamiyya is one of several military Islamist separatist groups based in and around the southern Philippines, in Bangsamoro (Jolo and Basilan) where for almost 30 years various Muslim groups have been engaged in an insurgency for an independent province in the country. The name of the group is derived from the Arabic ابو, abu ("father of") and sayyaf ("Swordsmith "). The group calls itself "Al-Harakat Al-Islamiyya" or the "Islamic Movement".

Since its inception in the early 1990s, the group has carried out bombings, kidnappings, assassinations and extortion in what they describe as their fight for an independent Islamic province in the Philippines.

The United States Department of State has classified the group as a terrorist group by adding it to the list of Foreign Terrorist Organizations. In 2002, fighting Abu Sayyaf became a mission of the American military's Operation Enduring Freedom and part of the U.S. War on Terror. The CIA has deployed paramilitary officers from their elite Special Activities Division to hunt down and kill or capture key terrorist leaders. Several hundred United States soldiers are also stationed in the area to mainly train local forces in counter terror and counter guerrilla operations, but as a status of forces agreement and under Philippine law are not allowed to engage in direct combat.

Abu Sabaya, whose real name is Aldam Tilao (1962 – June 21, 2002) was one of the leaders of the Abu Sayyaf in the southern Philippines until he was killed by soldiers of the Philippine Army in 2002. He was a former engineering student and police trainee and had lived in Saudi Arabia for several years [1][2].

Prior to his death, the United States government had placed a USD 5,000,000 reward on his arrest for the May 2001 kidnappings of two American missionaries and another American who was beheaded. According to the Philippine Army documents, Sabaya had dropped out of a criminology course to join the Moro National Liberation Front (M.N.L.F.), an Islamic rebel group, who trained him in bomb-making and assassination. When the M.N.L.F. signed a peace treaty with the Philippine government in 1996, Sabaya joined Filipinos working in Saudi Arabia. Upon his return to the Philippines he came into contact with Abdurajak Abubakar Janjalani, one of the founders of the Abu Sayyaf. Sabaya was accused of several hostage kidnappings. In Basilan, he was accused of being involved in 13 kidnappings incidents, including that of a Roman Catholic priest, schoolchildren and teachers. In reaction, the Philippine government offered a 5,000,000 peso reward for his capture.