| Phraates I 𐭐𐭓𐭇𐭕 | |
|---|---|
| Arsaces | |
 Coin of a Parthian ruler, possibly Phraates I. Minted at Hecatompylos between 185–132 BC | |
| King of the Arsacid dynasty | |
| Reign | 170/168–165/64 BC |
| Predecessor | Priapatius or Arsaces IV |
| Successor | Mithridates I |
| Died | 165/64 BC |
| Dynasty | Arsacid dynasty |
| Father | Priapatius |
| Religion | Zoroastrianism |
Phraates I (Parthian: 𐭐𐭓𐭇𐭕 Frahāt) was king of the Arsacid dynasty from 170/168 BC to 165/64 BC. He subdued the Mardians, conquered their territory in the Alborz mountains, and reclaimed Hyrcania from the Seleucid Empire. He died in 165/64 BC, and was succeeded by his brother Mithridates I (r. 165 – 132 BC), whom he had appointed his heir.