The Mujahedin-e Khalq (MEK), also known as the People's Mojahedin Organization of Iran (PMOI), is an Iranian opposition group founded on September 6, 1965, by Mohammad Hanifnejad, Said Mohsen, and Ali-Ashgar Badizadgan as a leftist student organization opposing the regime of Shah Mohammad Reza Pahlavi. Initially combining Marxist and Islamic ideologies, the MEK engaged in armed resistance against the monarchy and, after the 1979 Islamic Revolution, turned against the new Islamic Republic led by Ayatollah Khomeini, leading to severe repression and the exile of its members. The group established a military wing, the National Liberation Army of Iran (NLA), and operated from bases in Iraq under Saddam Hussein's protection until the 2003 U.S. invasion, during which many members were detained at Camp Ashraf.

Under the leadership of Massoud Rajavi, who disappeared in 2003, and his wife Maryam Rajavi, who serves as the public face and president-elect of the National Council of Resistance of Iran (NCRI), the MEK has advocated for the overthrow of the Iranian regime and the establishment of a democratic, secular government. The organization has a history of violent activities, including assassinations, bombings, and attacks on Iranian officials and dissidents, which led to its designation as a foreign terrorist organization by the United States in 1997, the European Union, and others. It was accused of collaborating with Iraqi forces during the Iran-Iraq War and suppressing internal dissent through cult-like practices, including forced divorces and ideological indoctrination, drawing criticism from former members and human rights groups.

In 2012, the U.S. delisted the MEK as a terrorist organization following its public renunciation of violence, absence of attacks for over a decade, and cooperation in relocating from Camp Ashraf. The group was transferred to Albania in 2016, where it now operates from a base near Tirana. The MEK continues to lobby internationally for regime change, forging alliances with Western politicians such as John Bolton, and faces ongoing allegations of terrorism by Iran while being condemned by some for authoritarian internal structures and misleading propaganda. Despite its delisting, it remains banned in Iran and several countries, and its influence networks involve diaspora support and political advocacy in Europe and the U.S.