Harakat al-Shabaab al-Mujāhideen, simply known as Al-Shabaab, or by its state name, the Islamic Emirate of Somalia, is a Sunni Islamist militant and political movement based in Somalia. It is involved in the ongoing Somali Civil War as an Islamist group, regularly invoking takfir to rationalize its terrorist attacks on Somali civilians and civil servants. Allied to the pan-Islamist militant organization al-Qaeda, it is also in a more limited capacity active elsewhere in East Africa, and has forged ties with other insurgent groups like AQIM and AQAP.
Formed in the mid-2000s as a youth militia within the wider military wing of the Islamic Courts Union, Al-Shabaab came to prominence during the 2006–2009 Ethiopian invasion and occupation of Somalia, during which it presented itself as a vehicle for the waging of armed resistance against the occupying Ethiopian army. In subsequent years, it gained popular support from Somalis and became a dominant force in south and central Somalia, defending large swathes of territory by fighting against the African Union Mission to Somalia and the Federal Government of Somalia, as well as the latter's transitional predecessor. Al-Shabaab gained international prominence due to its recruitment of foreign fighters, including fighters who are from Western countries. Countries including the United States, the United Kingdom, and the United Arab Emirates have designated it as a terrorist organization, and the United States has militarily intervened in order to fight against the group.