The Ptolemaic dynasty, (Ancient Greek: Πτολεμαῖοι, sometimes also known as the Lagids or Lagides, Ancient Greek: Λαγίδαι, from the name of Ptolemy I's father, Lagus) was a Macedonian Greek royal family which ruled the Ptolemaic Empire in Egypt during the Hellenistic period. Their rule lasted for 275 years, from 305 BC to 30 BC. They were the last dynasty of ancient Egypt.

Ptolemy, one of the six somatophylakes (bodyguards) who served as Alexander the Great's generals and deputies, was appointed satrap of Egypt after Alexander's death in 323 BC. In 305 BC, he declared himself King Ptolemy I, later known as "Soter" (saviour). The Egyptians soon accepted the Ptolemies as the successors to the pharaohs of independent Egypt. Ptolemy's family ruled Egypt until the Roman conquest of 30 BC.

All the male rulers of the dynasty took the name Ptolemy. Ptolemaic queens, some of whom were the sisters of their husbands, were usually called Cleopatra, Arsinoe or Berenice.

To cement their rule, the Ptolemaic rulers skillfully created composite Greek-Egyptian deities. In the Egyptian tradition, they identified themselves as gods and practiced brother-sister marriage.

The most famous member of the line was the last queen, Cleopatra VII, known for her role in the Roman political battles between Julius Caesar and Pompey, and later between Octavian and Mark Antony. Her apparent suicide at the conquest by Rome marked the end of Ptolemaic rule in Egypt. Cleopatra, who began her reign at age 17, was married at different times to two of her brothers, Ptolemy XIII and XIV, and later married her son, Caesarion.

Cleopatra VII was the last of the Ptolemies. 

But her real loves were the two famous Romans, with whom she made useful political alliances and conceived four children. Antony in particular seems to have gone native, embracing the luxurious lifestyle of the Egyptian court. Possibly a beauty – accounts differ, and the few extant images suggest otherwise – Cleopatra was without doubt clever and highly educated, a linguist who spoke not just Greek and Egyptian, but also Hebrew, Aramaic and other languages.