Qutbism is an exonym that refers to the Sunni Islamist beliefs and ideology of Sayyid Qutb, a leading Islamist revolutionary of the Muslim Brotherhood who was executed by the Egyptian government of Gamal Abdel Nasser in 1966. Influenced by the doctrines of earlier Islamists like Hasan al-Banna and Maududi, Qutbism advocates Islamic extremist violence in order to establish an Islamic government, in addition to promoting offensive Jihad. Qutbism has been characterized as an Islamofascist and Islamic terrorist ideology.

Sayyid Qutb's treatises deeply influenced numerous jihadist ideologues and organizations across the Muslim world. Qutbism has gained prominence due to its influence on notable Jihadist figures of contemporary era such as Abdullah Azzam, Osama bin Laden, Ayman al-Zawahiri, and Saif al-Adel. Its ideas have also been adopted by the Salafi-jihadist terrorist organization Islamic State (ISIL). It was one inspiration that influenced Ruhollah Khomeini in the development of his own ideology, Khomeinism.

Qutbist literature has been a major source of influence on numerous jihadist movements and organizations that have emerged since the 1970s. These include the Egyptian Islamic Jihad, al-Jama'ah al-Islamiyya, al-Takfir wal-Hijra, the Armed Islamic Group of Algeria (GIA), the Libyan Islamic Fighting Group (LIFG), al-Qaeda, al-Nusra Front, and the Islamic State (ISIL), and others that have sought to implement their strategy of waging offensive Jihad.

While adherents of Qutbism are referred to as Qutbists or Qutbiyyun (singular: Qutbi), they rarely refer to themselves with these names (i.e. the word is not an endonym); the name was first and still is used by the sect's opponents (i.e. it is an exonym).

The main tenet of the Qutbist ideology is that modern Muslims abandoned true Islam centuries ago, having instead reverted to jahiliyyah. Adherents believe that Islam must be re-established by Qutb's followers.

Qutb outlined his religious and political ideas in his book Ma'alim fi-l-Tariq ("Milestones"). Important principles of Qutbism include:^{[citation needed]}

Qutb declared Islam "extinct," which implied that any Muslims who do not follow his teachings are not actually Muslim. This was intended to shock Muslims into religious rearmament. When taken literally, takfir refers to ex-communication, thereby declaring all non-Qutbist Muslims to be apostates in violation of Sharia law. Violating this law could potentially be punished by death, according to Islamic law.

Because of these serious consequences, Muslims have traditionally been reluctant to practice takfir, that is, to pronounce professed Muslims as unbelievers, even when in violation of Islamic law. This prospect of fitna, or internal strife, between Qutbists and "takfir-ed" mainstream Muslims, led Qutb to conclude that the Egyptian government was irredeemably evil. As a result, he helped to plan a thwarted series of assassinations of Egyptian officials, the discovery of which let to Qutb's trial and eventual execution. Due in part to this teaching, Qutb's ideology remains controversial among Muslims.