See main article: 1991 Australian Open.
Monica Seles defeated Jana Novotná in the final, 5–7, 6–3, 6–1 to win the women's singles tennis title at the 1991 Australian Open. She became the first woman in the Open Era to win the Australian Open after saving a match point, doing so in the semifinals against Mary Joe Fernández.
Steffi Graf was the three-time defending champion, but lost to Novotná in the quarterfinals.
The seeded players are listed below. Monica Seles is the champion; others show the round in which they were eliminated.
See main article: 1991 Australian Open – Women's singles qualifying.