The 1991 Australian Open was a tennis tournament played on outdoor hard courts at Flinders Park in Melbourne in Victoria in Australia.

It was the 79th edition of the Australian Open and was held from 14 through 27 January 1991.

Boris Becker defeated Ivan Lendl 1–6, 6–4, 6–4, 6–4 Monica Seles defeated Jana Novotná 5–7, 6–3, 6–1 Scott Davis / David Pate defeated Patrick McEnroe / David Wheaton 6–7(4–7), 7–6(10–8), 6–3, 7–5 Patty Fendick / Mary Joe Fernández defeated Gigi Fernández / Jana Novotná 7–6(7–4), 6–1 Jo Durie / Jeremy Bates defeated Robin White / Scott Davis 2–6, 6–4, 6–4 Thomas Enqvist defeated Stephen Gleeson 7–6, 6–7, 6–1 Nicole Pratt defeated Kristin Godridge 6–4, 6–3 Grant Doyle / Joshua Eagle defeated Jamie Holmes / Paul Kilderry 7–6, 6–4 Karina Habšudová / Barbara Rittner defeated Joanne Limmer / Angie Woolcock 6–2, 6–0