Antiochus I Soter ( i.e.

Antiochus the Savior, unknown - 261 BCE), is a king of the Hellenistic Seleucid Empire.

He reigns in 281 BCE – 261 BCE.

Antiochus I is half Persian, his mother Apama being one of the eastern princesses whom Alexander the Great had given as wives to his generals in 324 BCE.

In 294 BCE, prior to the death of his father Seleucus I, Antiochus marries his stepmother, Stratonice, daughter of Demetrius Poliorcetes.

His elderly father reportedly instigated the marriage after discovering that his son was in danger of dying of lovesickness.

Stratonice bears five children to Antiochus: Seleucus (he was executed for rebellion), Laodice, Apama II, Stratonice of Macedon and Antiochus II Theos, who succeeds his father as king.