The Uprising of Ivaylo is an uprising of the Bulgarian peasantry against the Emperor Constantine Tikh and the Bulgarian nobility.

The revolt is fueled by resentment at the beginning feudalization of the Bulgarian Empire, as well as by the failure to confront the Mongol menace over northeastern Bulgaria, especially the region of Dobrudzha.

Ivaylo proves to be a successful general, defeating the Mongols and the Tsar's armies, and forced the nobility to recognize him as Emperor of Bulgaria.The East Roman (Byzantine) Emperor Michael VIII Palaiologos tries to exploit this situation and to help the nobility to quell the rebellion, but the imperial forces suffer two major defeats at the hands of Ivaylo.

The Mongol intervention, however, forces him to flee to the important fortress of Drastar (Silistra), where he is besieged.

Thereupon, the nobility uses his absence from the capital Tarnovo to proclaim George Terter I as emperor.

Surrounded by enemies and with diminished support, Ivaylo has to flee to Nogai Khan and is later murdered by the Mongols.