Demetrius I, called Poliorcetes, was a Macedonian Greek nobleman and military leader who became king of Macedon between 294–288 BC. A member of the Antigonid dynasty, he was the son of its founder, Antigonus I Monophthalmus and his wife Stratonice, as well as the first member of the family to rule Macedon in Hellenistic Greece.

The Antigonid dynasty was a Macedonian Greek royal house which ruled the kingdom of Macedon during the Hellenistic period. Founded by Antigonus I Monophthalmus, a general and successor of Alexander the Great, the dynasty first came to power after the Battle of Salamis in 306 BC and ruled much of Hellenistic Greece from 294 until their defeat at the Battle of Pydna in 168 BC, after which Macedon came under the control of the Roman Republic.