Arcadius (Latin: Flavius Arcadius Augustus; 377/378 – 1 May 408) is the Byzantine Emperor from 395 until his death in 408.

He is the eldest son of Theodosius I and his first wife Aelia Flaccilla, and brother of the Western Emperor Honorius.

A weak ruler, his reign is dominated by a series of powerful ministers and by his wife, Aelia Eudoxia.