In Sophocles' Oedipus, there are only three women in the play, two of which (Antingone and Ismene) are only bit players. Antigone's role is to escort her blind father at the end as he exiles himself from the city. She and her sister are mainly in a support role.
Only Jocasta is a major character. As such, she is a:
Mother-figure: to Oedipus and Creon. She urges the two to reconcile their differences in the motherly tones of a matriarch.
Queen: she is above the citizens in the play. She stands on a higher platform than them literally. While they suffer from the plague, she is in a position of health and opulence (until the end)
Supplient: She thinks she is better than she really is. At the end, she provides vision of unmitigated suffering and helplessness. She kills herself rather than live with the guilt of infanticide and incest.
Blocker of Fate: She attempts to protect and shield the royal family from fate's cruelty by being a non-believer in it and the the gods.
Foil: she is a reflection of Oedipus. She parallels Oedipus' discovery of his past. Her realization precedes his. She commits suicide, while he blinds himself.
Anti-tragic hero: Whereas her suicide is a symbol of weakness and refusal to suffer and know the truth, Oedipus only blinds himself, taking all the sins of the family upon himself (suffering, guilt, truth). As such, he is the tragic hero, and she is not.