Basiliscus (d. 476/477) is Eastern Roman (Byzantine) Emperor from 475 to 476.

A member of the House of Leo, he comes to power when Emperor Zeno is forced out of Constantinople by a revolt.

Basiliscus is the brother of Empress Aelia Verina, the wife of Emperor Leo I (457–474).

His relationship with the Emperor allows him to pursue a military career that, after minor initial successes, ends in 468, when he leads the disastrous Roman invasion of Vandal Africa, in one of the largest military operations of Late Antiquity.

Basiliscus succeeds in seizing power in 475, exploiting the unpopularity of Emperor Zeno, the "barbarian" successor to Leo, and a plot organized by Verina that had caused Zeno to flee Constantinople.

However, during his short rule, Basiliscus alienates the fundamental support of the Church and the people of Constantinople, promoting the Miaphysite christological position in opposition to the Chalcedonian faith.

Also, his policy of securing his power through the appointment of loyal men to key roles antagonizes many important figures in the imperial court, including his sister Verina.

So, when Zeno tries to regain his empire, he finds virtually no opposition, triumphantly entering Constantinople, and capturing and killing Basiliscus and his family.

The struggle between Basiliscus and Zeno impedes the Eastern Empire's ability to intervene in the fall of the Western Roman Empire, which happensin early September 476.

When the chieftain of the Heruli, Odoacer, deposes Western Emperor Romulus Augustus, sending the imperial regalia to Constantinople, Zeno had just regained his throne, and he can only appoint Odoacer dux of Italy, thereby ending the Western Roman Empire.