Shahpur II (310-379) was a Persian king during whose reign the Sassanian dynasty reached a new height in military power and territorial expansion.

Posthumous son of Hormozd II, Shahpur was elected king before his birth, or possibly as an infant. During his minority reign Persia had a weak government of regents and suffered raids from its neighbors, particularly the Arabs who invaded southern Persia. Rome, however, which had gained some of the western Persian cities in Mesopotamia during the reign of Narse, Shahpur's grandfather, left Persia in peace.

Once grown up, Shahpur proved a formidable soldier and a capable ruler. After subduing the Arabs and conquering Bahrain on the southern littoral of the Persian Gulf, he turned his attention to his western frontiers with a view to restoring the Persian provinces lost earlier to Rome and establishing Persian power over Armenia and Iberia. Perso-Roman relations had latterly become...