|King of Epirus|
|Reign||390 - 370 BC|
|Successor||Neoptolemus I of Epirus|
|Issue||Neoptolemus I of Epirus|
|Religion||Ancient Greek religion|
Alcetas I (Greek: Ἀλκέτας) (390/385 – 370 BC) was a king of Epirus, the son of Tharrhypas.
Alcetas was expelled from his kingdom for unknown reasons, and took refuge with Dionysius I of Syracuse, by whom he was reinstated.
After Alcetas' restoration, he allied with the Athenians, and with Jason of Pherae, the Tagus of Thessaly. In 373 he appeared at Athens with Jason, for the purpose of defending the Athenian general Timotheus, who, through their influence, was acquitted.
Upon Alcetas' death, the kingdom was divided between his two sons, Neoptolemus I and Arybbas.