| Demetrius I Soter | |
|---|---|
 Silver tetradrachm of Demetrios I Soter, minted in Soloi, featuring a portrait of Demetrios on the obverse. SC 1611.3 | |
| Basileus of the Seleucid Empire | |
| Reign | November 162 – June 150 BC |
| Predecessor | Antiochus V Eupator |
| Successor | Alexander Balas |
| Born | 185 BC |
| Died | June 150 BC (aged 34 or 35) |
| Spouse | Laodice V |
| Issue | Demetrius II Nicator Antiochus VII Sidetes Antigonus |
| Dynasty | Seleucid |
| Father | Seleucus IV Philopator |
| Mother | Laodice IV |
Demetrius I Soter (Ancient Greek: Δημήτριος Α` ὁ Σωτήρ, Dēmḗtrios ho Sōtḗr, "Demetrius the Saviour"; 185 – June 150 BC) reigned as king of the Hellenistic Seleucid Empire from November 162 to June 150 BC. Demetrius grew up in Rome as a hostage, but returned to Greek Syria and overthrew his young cousin Antiochus V Eupator and regent Lysias. Demetrius took control during a turbulent time of the Empire, and spent much of his time fighting off revolts and challenges to his power from threats such as Timarchus and Alexander Balas.