The 1977 New South Wales Open, also known by its sponsored name Marlboro New South Wales Open, was a combined men's and women's tennis tournament played on outdoor grass courts at the White City Stadium in Sydney, Australia. The men's was part of the 1977 Colgate-Palmolive Grand Prix circuit. It was the 85th edition of the event and was held from 12 December through 18 January 1977. The singles titles were won by Evonne Goolagong Cawley and Roscoe Tanner. Defending champion Tony Roche was unable to participate due to a stomach muscle injury.
Finals
Men's singles
Roscoe Tanner defeated Brian Teacher 6–3, 3–6, 6–3, 6–7, 6–4
Women's singles
Evonne Goolagong Cawley defeated Sue Barker 6–2, 6–3
Men's doubles
John Alexander / Phil Dent defeated Ray Ruffels / Allan Stone 7–6, 2–6, 6–3
Women's doubles
Evonne Goolagong Cawley / Helen Gourlay Cawley defeated Mona Guerrant / Kerry Reid 6–0, 6–0