John Kourkouas (fl.

circa 915–946), also transliterated as Kurkuas or Curcuas, is one of the most important generals of the Byzantine Empire.

His success in battles against the Muslim states in the East definitively reverses the course of the centuries-long Byzantine–Arab Wars and begins Byzantium's 10th century "Age of Conquest".

Kourkouas belongs to a family of Armenian descent that produces several notable Byzantine generals.

As commander of an imperial bodyguard regiment, Kourkouas is among the chief supporters of Emperor Romanos I Lekapenos (reigned 920–944) and had facilitated the latter's rise to the throne.

In 923, Kourkouas is appointed commander-in-chief of the Byzantine armies along the eastern frontier, facing the Abbasid Caliphate and the semi-autonomous Muslim border emirates.

He keeps this post for more than twenty years, overseeing decisive Byzantine military successes that alter the strategic balance in the region.

During the 9th century, Byzantium had gradually recovered its strength and internal stability while the Caliphate had become increasingly impotent and fractured.

Under Kourkouas's leadership, the Byzantine armies advance deep into Muslim territory for the first time in almost 200 years, expanding the imperial border.

The emirates of Melitene and Qaliqala are conquered, extending Byzantine control to the upper Euphrates and over western Armenia.

The remaining Iberian and Armenian princes become Byzantine vassals.

Kourkouas also plays a role in the defeat of a major Rus' raid in 941 and recovers the Mandylion of Edessa, an important and holy relic believed to depict the face of Jesus Christ.

He is dismissed in 944 as a result of the machinations of Romanos Lekapenos's sons but restored to favor by Emperor Constantine VII (r. 913–959), serving as imperial ambassador in 946.

His subsequent fate is unknown.