Wahhabism (Arabic: Al-Wahhābīyya الوهابية) or Wahabism is a name sometimes applied to the conservative 18th century reformist call of Sunni Islam attributed to Muhammad ibn Abd-al-Wahhab, an Islamic scholar from what is today known as Saudi Arabia, who became known for advocating a return to the practices of the first three generations of Islamic history. Wahhabism formed the creed upon which the kingdom of Saudi Arabia was founded and is the dominant form of Islam found in Saudi Arabia, and Qatar, as well as some pockets of Somalia, Algeria and Mauritania. It is now often referred to as a "sect" or "branch" of Islam, though its supporters reject such designations.

The primary doctrine of Wahhabism is Tawhid, or the uniqueness and unity of God. Ibn Abdul Wahhab was influenced by the writings of scholars such as Ibn Taymiyya and rejected medieval interpretations of Islam, relying on Quran and hadith. He preached against a "perceived moral decline and political weakness" in the Arabian peninsula and condemned idolatry, the popular cult of saints, and shrine and tomb visitation.

Note: Most suicide bombers in Iraq are Wahhabies.