The United Front (in full: United Islamic Front for the Salvation of Afghanistan; acronym: UF; Persian: ‏ جبهه متحد اسلامی ملی برای نجات افغانستان‎, Jabha-yi Muttahid-i Islami-yi Milli bara-yi Nijat-i Afghanistan), known in the West and Pakistan as the Northern Alliance, was a military-political umbrella organization created by the Islamic State of Afghanistan in late 1996 under the leadership of the then Defense Minister Ahmad Shah Massoud. The United Front fought as a resistance force against the Afghan Taliban who according to many sources were supported by Pakistan's military and Al-Qaeda. The UF united all ethnic groups of Afghanistan including Tajiks, Pashtuns, Hazaras, Uzbeks, Turkmen and others.

The United Front was established in late 1996 as a resistance force against the Taliban by opposition factions representing all ethnic groups in Afghanistan. Since early 1999, Ahmad Shah Massoud was the only main leader able to defend his territory against the Taliban and their allies and as such remained as the main de facto political and military leader of the United Front recognized by members of all the different ethnic groups. Massoud decided on the main political line and the general military strategy of the alliance. A part of the United Front military factions such as Junbish-i Milli or Hezb-e Wahdat, however, did not fall under the direct control of Massoud but remained under their respective regional or ethnic leaders.

Ahmad Shah Massoud (احمد شاه مسعود Aḥmad Šāh Mas'ūd; September 2, 1953 – September 9, 2001) was a political and military leader in Afghanistan. He was a central figure, known as the "Lion of Panjshir", in the resistance against the Soviet occupation between 1979 and 1989, fought against the alliance of Gulbuddin Hekmatyar in the early 1990s, and led resistance against the Taliban regime between 1996 and 2001. Massoud was assassinated on September 9, 2001, two days before the attacks of September 11.

Massoud was an Afghan-Tajik Sunni Muslim born in the Panjshir in northern Afghanistan. He studied engineering at Kabul University in the 1970s, where he became involved with Muslim anti-communist movements around Burhanuddin Rabbani. He led an uprising against the Soviet-backed communist government in his native Panjshir in 1979. His role in the following period of armed resistance against the Soviet occupation forces earned him the nickname of "Lion of Panjshir" (شیر پنجشیر). Following the withdrawal of Soviet troops from Afghanistan the Wall Street Journal named Massoud "the Afghan who won the Cold War". In 1992, he was appointed minister of defense in the government of the newly established Islamic State of Afghanistan by the peace and power-sharing agreement Peshawar Accords. He led the Islamic State's defense against attacks by Gulbuddin Hekmatyar's alliance of militias which were backed by Pakistan. Following the rise of the Taliban in 1996, Massoud, who rejected the Taliban's and Al-Qaeda's extremist interpretation of Islam, returned to the role of an armed opposition leader, serving as the military and political leader of the multiethnic United Islamic Front (also known in the West as Northern Alliance). In 1997, he helped end the civil war in neighboring Tajikistan urging parties to accept a United Nations peace plan.