Cleopatra Selene I is the daughter of Ptolemy VIII Physcon by his niece Cleopatra III of Egypt.

She is the wife of three different kings; including queen consort to Ptolemy IX Lathyros of Egypt, and later queen of Syria.

Originally she was named Selene, only adding the Ptolemaic throne name Cleopatra after her marriage with Lathyros, whom she marries after his wife, her sister Cleopatra IV, is forced out by her mother (115 BCE).

Selene is not, however, made co-ruler, unlike many of the sister-wives of Ptolemaic kings.

She bears Lathyros at least one daughter, Berenice III and two sons, including Ptolemy XII and possibly another son, also named Ptolemy.