The 2003 Australian Open was a tennis tournament held in 2003. It was the first Grand Slam event of the 2003 ATP Tour and the 2003 WTA Tour. It was the 91st edition of the event and attracted 512,225 spectators. Thomas Johansson could not defend his 2002 title due to an injury which would rule him out for all of 2003. Jennifer Capriati was unsuccessful in her title defence, being defeated in the first round by German Marlene Weingärtner. Andre Agassi won his fourth Australian Open and final Grand Slam title, defeating Rainer Schüttler in a lopsided final. Serena Williams defeated her sister Venus in the final in three sets, to win her fourth consecutive Grand Slam title to hold all four Grand Slam titles at once.

Seniors

Men's singles

🇺🇸 Andre Agassi defeated 🇩🇪 Rainer Schüttler, 6–2, 6–2, 6–1

Women's singles

🇺🇸 Serena Williams defeated 🇺🇸 Venus Williams, 7–6(7–4), 3–6, 6–4

Men's doubles

🇫🇷 Michaël Llodra / 🇫🇷 Fabrice Santoro defeated Mark Knowles / 🇨🇦 Daniel Nestor, 6–4, 3–6, 6–3

Women's doubles

🇺🇸 Serena Williams / 🇺🇸 Venus Williams defeated 🇪🇸 Virginia Ruano Pascual / 🇦🇷 Paola Suárez, 4–6, 6–4, 6–3

Mixed doubles

🇺🇸 Martina Navratilova / 🇮🇳 Leander Paes defeated Eleni Daniilidou / 🇦🇺 Todd Woodbridge, 6–4, 7–5

Juniors

Boys' singles

🇨🇾 Marcos Baghdatis def. Florin Mergea, 6–4, 6–4

Girls' singles

🇨🇿 Barbora Strýcová defeated 🇺🇦 Viktoriya Kutuzova, 0–6, 6–2, 6–2

Boys' doubles

🇺🇸 Scott Oudsema / 🇺🇸 Phillip Simmonds defeated Florin Mergea / Horia Tecău, 6–4, 6–4

Girls' doubles

🇦🇺 Casey Dellacqua / 🇦🇺 Adriana Szili defeated 🇨🇿 Petra Cetkovská / 🇨🇿 Barbora Strýcová, 6–3, 4–4, ret.

Wheelchair

Men's wheelchair singles

🇦🇺 David Hall defeated Robin Ammerlaan, 6–1, 7-6

Women's wheelchair singles

Esther Vergeer defeated 🇦🇺 Daniela Di Toro, 2–6, 6–0, 6-3

Seeds

Withdrawn players: 🇬🇧 Tim Henman, 🇩🇪 Tommy Haas, 🇸🇪 Thomas Johansson, Marcelo Ríos, 🇬🇧 Greg Rusedski, 🇫🇷 Paul-Henri Mathieu, 🇫🇷 Arnaud Clément; Martina Hingis, 🇫🇷 Amélie Mauresmo, Jelena Dokic.

Men's singles

Women's singles