Sanusi or Senussi (both: sənōˈsĭ) [key], Arabic Sanusiyya, a political-religious organization in Libya and Sudan founded in Mecca in 1837 by Muhammad bin Ali al-Sanusi (1791–1859), known as the Grand Sanusi. Sanusi was concerned with both the perceived decline of Islamic thought and the weakening of the Islamic world. His call for political activism was influenced by the Wahhabi movement in Arabia, to which he eclectically added some Sufi teachings from several different Sufi orders. The Sanusi unsuccessfully fought (1902–13) French expansion in the Sahara, and in 1911 the Italian invasion of Libya forced them to concentrate there. During World War I they attacked British-occupied Egypt. A grandson of the Grand Sanusi became King Idris I of Libya in 1951. In 1969, the king was overthrown by a coup led by Colonel Muammar al-Qaddafi. A third of the population in Libya, and fewer in Sudan, are still affiliated with the Sanusi organization.
See E. E. Evans-Pritchard, The Sanusi of Cyrenaica (1949, repr. 1963); N. A. Ziadeh, Sanusiyah (1958, repr. 1983).