Two Australian Opens were held in 1977 because the tournament’s calendar was being shifted. One edition took place in January, and a second edition was staged in December.
The January tournament was held at Kooyong in Melbourne from 3 to 9 January. Kerry Melville Reid won the women’s singles title, while Roscoe Tanner captured the men’s singles championship. The December edition ran from 19 to 31 December, with Vitas Gerulaitis and Evonne Goolagong Cawley winning the singles titles.
This unusual scheduling created two separate tournaments carrying the 1977 label. It was not a duplicate final or a replay; each edition had its own draw, champions and results.
The calendar change also explains why the Australian Open later moved between December and January. The event remained in a late-year slot through 1985 before returning to January, causing the tournament to be skipped entirely in 1986.