Eusebia was the second wife of Roman emperor Constantius II. The main sources for the knowledge about her life are Julian's panegyric "Speech of Thanks to the Empress Eusebia", as well as several remarks by the historian Ammianus Marcellinus.

Constantius II was Roman emperor from 337 to 361. His reign saw constant warfare on the borders against the Sasanian Empire and Germanic peoples, while internally the Roman Empire went through repeated civil wars, court intrigues, and usurpations. His religious policies inflamed domestic conflicts that would continue after his death.