2018 Australian Open – Men's singles

Defending champion Roger Federer defeated Marin Čilić in the final, 6–2, 6–7(5–7), 6–3, 3–6, 6–1 to win the men's singles tennis title at the 2018 Australian Open. It was his record-equalling sixth Australian Open title (tied with Roy Emerson and Novak Djokovic), and his record-extending 20th and last major title overall. With the win, Federer became the oldest man to win a major singles title since Ken Rosewall in 1972. This was the tenth time that Federer defended a major title, the last time being at the 2008 US Open. Čilić became the first Croatian to reach an Australian Open singles final.

This was the first time since the 2008 Wimbledon Championships that two unseeded players (Chung Hyeon and Kyle Edmund) reached the semifinals of a men's singles major, and the first time at the Australian Open since 1999. Chung became the first South Korean player to reach a major quarterfinal and semifinal.

Seeds
All seedings per ATP rankings. • 🇪🇸 Rafael Nadal (quarterfinals, retired)

• Roger Federer (champion)

•  🇧🇬 Grigor Dimitrov (quarterfinals)

•  🇩🇪 Alexander Zverev (third round)

•  🇦🇹 Dominic Thiem (fourth round)

•   Marin Čilić (final)

•  🇧🇪 David Goffin (second round)

•  🇺🇸 Jack Sock (first round)

•   Stan Wawrinka (second round)

• 🇪🇸 Pablo Carreño Busta (fourth round)

•  Kevin Anderson (first round)

• 🇦🇷 Juan Martín del Potro (third round)

• 🇺🇸 Sam Querrey (second round)

• 🇷🇸 Novak Djokovic (fourth round)

• 🇫🇷 Jo-Wilfried Tsonga (third round)

• 🇺🇸 John Isner (first round)

• 🇦🇺 Nick Kyrgios (fourth round)

• 🇫🇷 Lucas Pouille (first round)

• 🇨🇿 Tomáš Berdych (quarterfinals)

• 🇪🇸 Roberto Bautista Agut (first round)

• 🇪🇸 Albert Ramos-Viñolas (third round)

• 🇨🇦 Milos Raonic (first round)

• 🇱🇺 Gilles Müller (third round)

• 🇦🇷 Diego Schwartzman (fourth round)

• 🇮🇹 Fabio Fognini (fourth round)

• 🇫🇷 Adrian Mannarino (third round)

• 🇩🇪 Philipp Kohlschreiber (first round)

• 🇧🇦 Damir Džumhur (third round)

• 🇫🇷 Richard Gasquet (third round)

• 🇷🇺 Andrey Rublev (third round)

•  Pablo Cuevas (second round)

• 🇩🇪 Mischa Zverev (first round, retired)