2019 Australian Open – Women's singles

Naomi Osaka defeated Petra Kvitová in the final, 7–6^(7–2), 5–7, 6–4 to win the women's singles tennis title at the 2019 Australian Open. It was her first Australian Open title and second major title overall. With the win, Osaka became the world No. 1, and the first player since Jennifer Capriati to win their first two major titles at consecutive events. Ten players were in contention for the world No. 1 ranking: Kvitová, Osaka, reigning world No. 1 Simona Halep, Sloane Stephens, Karolína Plíšková, Angelique Kerber, Elina Svitolina, Kiki Bertens, Aryna Sabalenka and Daria Kasatkina.

Caroline Wozniacki was the defending champion, but lost in the third round to Maria Sharapova.

This was the first Australian Open to feature a final-set tiebreak. When the score in a final set reached 6–6, the first player to reach 10 points and lead by at least 2 points won the set (and the match). Katie Boulter and Ekaterina Makarova became the first players to contest this tiebreak in the main draw, with Boulter emerging victorious.

This tournament marked the major main-draw debut of future world No. 1 and five-time major champion Iga Świątek; she lost to Camila Giorgi in the second round. Amanda Anisimova became the first player born in the 21st century to reach the fourth round of a singles major. Ashleigh Barty was the first Australian to reach the quarterfinals since Jelena Dokic in 2009.

For the first time since 2009 Wimbledon, all of the top eight seeds reached the third round at a women's singles major.