Hizb ut-Tahir (HT) is an Islamist political movement, which states it wants to reestablish the Caliphate in traditional Muslim lands, but by nonviolent means. It also wants to build Muslim community in the West.  Ahmed Rashid wrote that it is theologically close to Wahhabism, but is basically nonviolent, although it has been banned in Germany and there is pressure to do so in Britain. 
It was formed in 1952 by Taqiuddin an-Nabhani, a Palestinian Jurist; its current leader is Ata ibn Khaleel Abu Rushta.
The party has been banned in a wide range of countries, from western democracies such as Germany and Denmark; to Muslim states such as Pakistan, Jordan, Turkey, and Bangladesh; to the dictatorships of Uzbekistan and Syria. Its status in the United Kingdom is an active Parliamentary discussion. Its German banning came from cooperation with neo-Nazis, abd although the group claims to be are anti-Zionist rather than anti-Semitic. In Denmark, it distributed literature calling on Muslims to "kill [Jews] wherever you find them, and turn them out from where they have turned you out." It called the Uzbek dictator "the Jew Karimov", although he is not Jewish.
Until recently, it had not been evident in the United States. It held its first public event, a conference entitled "Fall of Capitalism and Rise of Islam," at the Hilton in Oak Park, Illinois, on 19 July 2009. "Although HT America's Web site states that the group "does not work in the West to change the system of government," speakers at the conference focused on HT's larger agenda of establishing a global Islamic caliphate, or Islamic rule worldwide, which entails ousting existing governments."  Jarret Brachman wrote that Zachary Chesser had converted to Islam after attending one of the group's events. 
- Media Information Pack, Hizb ut-Tahrir Britain
- Ahmed Rashid (2006), Descent into Chaos: The United States and the Failure of Nation Building in Pakistan, Afghanistan and Central Asia, Viking, ISBN 9780670019700, pp. 164-165
- Christian Caryl (22 December 2009), "Reality Check: The Party’s Not Over: Does Islamist party Hizb-ut-Tahrir pose a threat to Western society? The answer may well be yes -- but that doesn't mean it should be banned.", Foreign Policy (magazine)
- Hizb ut-Tahrir Emerges in America: Introduction, Anti-Defamation League, 12 July 2010
- Jarret Brachman (29 July 2010), "My Pen Pal, the Jihadist", Foreign Policy (magazine)