See main article: 1978 Australian Open.
Guillermo Vilas defeated John Marks in the final, 6–4, 6–4, 3–6, 6–3 to win the men's singles tennis title at the 1978 Australian Open. It was his first Australian Open title and third major singles title overall.
Vitas Gerulaitis was the reigning champion, but did not compete this year.
This tournament was the final major appearance for former four-time champion Ken Rosewall.
The seeded players are listed below. Guillermo Vilas is the champion; others show the round in which they were eliminated.
Guillermo Vilas (champion) José Luis Clerc (first round)
Arthur Ashe (semifinals) Tim Gullikson (second round)
Wojtek Fibak (third round)
John Alexander (quarterfinals) Ken Rosewall (third round) Victor Amaya (second round) Hank Pfister (semifinals)
Yannick Noah (first round) Tony Roche (quarterfinals)
Peter Feigl (quarterfinals) Kim Warwick (third round) Geoff Masters (first round)
Bernard Mitton (second round) Allan Stone (third round)See main article: 1978 Australian Open – Men's singles qualifying.