Arthur Cusack (born 1919, Maryborough, Queensland; died 2000, Brisbane) was an Australian Olympic swimming coach in the 1950s and 1960s.
In 1938, at 18 years old, Cusack became the Secretary of the newly formed Maryborough Amateur Swimming Club.
He coached Ann Margaret Nelson, a finalist in the 110-yard backstroke in the Cardiff 1958 British Empire and Commonwealth Games, where she finished fifth with a time of 1.15.5, behind Judy Grinham of England.
Arthur Cusack introduced a backstroke turn and a bent-arm stroke to assist David Theile in his quest for Olympic gold.
This new turning technique was seen as suspect by some officials during the heats of the 100m backstroke at the 1956 Olympics, who wanted Theile to give a demonstration for their review, a request Cusack refused.