Jocasta was the daughter of Menoeceus, a descendant of Cadmus and the Spartoi, and sister of Creon (and, in some lists, Hipponome). Married to King Laius, she became queen of Thebes and bore a son, Oedipus, whom Laius exposed after an oracle warned that the child would kill him and marry his wife.

Years later, still ignorant of Oedipus's identity, she married him when he freed Thebes from the Sphinx, and bore Antigone, Eteocles, Polynices, and Ismene — becoming both mother and grandmother to those children.

Laius, drunk despite Delphi's warning, fathered Oedipus; he pierced the infant's ankles and had him exposed on Cithaeron. The child was reared at Corinth by Polybus and Merope (or Periboea). Grown, Oedipus fled Corinth after Delphi foretold he would kill his father and marry his mother — believing Polybus and Merope to be his parents — and at a narrow road killed Laius in a quarrel.

At Thebes, Creon offered the throne and Jocasta's hand to whoever solved the Sphinx's riddle. Oedipus succeeded and married Jocasta, completing the prophecy. Homer already knows her (as Epicaste) in the underworld episode of the Odyssey.

In Sophocles, when plague forces the discovery of patricide and incest, Jocasta hangs herself and Oedipus blinds himself with her brooches. In Euripides's Phoenissae she survives the revelation, tries to reconcile Eteocles and Polynices, and kills herself only after they die by each other's hands. Odysseus later sees her shade in Hades.

Medieval tradition includes her among Boccaccio's famous women. Modern psychology borrows her name for the "Jocasta complex," a counterpart discourse to the Oedipus complex.