The term "Anarchy at Samarra" refers to the period 861–870 in the history of the Abbasid Caliphate, which is marked by extreme internal instability and the violent succession of four caliphs, who become puppets in the hands of powerful rival military groups.

The term derives from the then capital and seat of the caliphal court, Samarra.

The "anarchy" begins in 861, with the murder of Caliph al-Mutawakkil by his Turkish guards.

His successor, al-Muntasir, rules for six months before his death, possibly poisoned by the Turkish military chiefs.

He is succeeded by al-Musta'in.

Divisions within the Turkish military leadership enable Musta'in to flee to Baghdad in 865 with the support of some Turkish chiefs and the Tahirids, but the rest of the Turkish army chooses a new caliph in the person of al-Mu'tazz and besieges Baghdad, forcing the city's capitulation in 866.

Musta'in is exiled and executed.

Mu'tazz is able and energetic, and tries to control the military chiefs and exclude the military from civil administration.

His policies are resisted, and in July 869, he, too, is deposed and killed.

His successor, al-Muhtadi, also tries to reaffirm the Caliph's authority, but he, too, is killed in June 870.

With Muhtadi's death and the ascension of al-Mu'tamid, the Turkish faction around Musa ibn Bugha, closely associated with Mu'tamid's brother and vizier al-Muwaffaq, becomes dominant in the caliphal court, ending the "anarchy".

Although the Abbasid Caliphate is able to stage a modest recovery in the following decades, the troubles of the "Anarchy at Samarra" inflict great and lasting damage on the structures and prestige of the Abbasid central government, encouraging and facilitating secessionist and rebellious tendencies in the Caliphate's provinces.