Ajla Tomljanović (/ˈaɪlə təmˈjɑːnəvɪtʃ/ EYE-lə təm-YAH-nə-vitch;[1] Croatian: [âjla tomʎǎːnoʋitɕ];[2] born 7 May 1993) is an Australian professional tennis player.

Tomljanović was an accomplished junior player, having won the 2009 Australian Open girls' doubles title with Christina McHale.

[7] In the latter stages of 2014, Tomljanović took up permanent residency in Brisbane to be closer to her cousin Isabella Bozicevic's family who were based in the neighbouring Gold Coast as well as begin training at the Queensland Tennis Centre and in doing so switched allegiances to represent Australia in the four Grand Slams.

[8] In 2018, her application for Australian citizenship was approved which allowed her to begin representing her adopted country at WTA Tour events as well as competing for Australia in the Fed Cup.

[6][10] Tomljanović won the 2009 Australian Open girls' doubles title with Christina McHale, defeating Aleksandra Krunić and Sandra Zaniewska in the final.

[11] Tomljanović played her first professional ITF Circuit event in October 2008 in Mexico City, and lost to Estefanía Craciún in the semifinals.

[12][13] Tomljanović then suffered three consecutive losses in the second rounds of Redding, California, Osprey, Florida, and Makarska, Croatia, losing to Rika Fujiwara, Kateřina Kramperová and Ana Savić, respectively.

[15] During the preseason, Tomljanović began working with coach David Taylor, former Australian Fed Cup captain, who had just parted company with Samantha Stosur.

[27] Tomljanović qualified for the main draw of the Porsche Tennis Grand Prix by beating Carina Witthöft, Sachia Vickery, and fifth seed Mona Barthel.

Seeded eighth at the first edition of the Tianjin Open, Tomljanović reached the quarterfinals defeating qualifier Nadiia Kichenok and Duan Yingying.

[60] Tomljanović started the US Open Series at the Stanford Classic where she advanced to the quarterfinals defeating Vitalia Diatchenko and seventh seed Madison Keys.

[75] At the Revolution Technologies Pro Tennis Classic in Indian Harbour Beach, she lost in the first round to American wildcard Victoria Duval.

[76] Competing as a wildcard at the Boyd Tinsley Clay Court Classic, Tomljanović advanced to the semifinals where she lost to Caroline Dolehide.

[77] At the LTP Charleston Pro, she retired after losing the first set 4–6 to top seed Madison Brengle due to a hip injury.

[81] At the Stanford Classic, she retired in her first-round match due to a shoulder injury, after losing the first set 2–6 to sixth seed CoCo Vandeweghe.

Tomljanović lost in the first round of the Australian Open to Lucie Šafářová before reaching consecutive semifinals on WTA 125 tournaments, at Newport Beach and Indian Wells.

[106] When the WTA resumed tournaments in August, Tomljanović competed at the Lexington Challenger where she lost in the first round to fifth seed Yulia Putintseva.

At the first edition of the Serbia Open, she retired during her second-round match against seventh seed Rebecca Peterson due to a hip injury.

[121] Starting the grass-court season at the Birmingham Classic, Tomljanović upset top seed Elise Mertens in a three-set battle in the first round.

[124] At Wimbledon, she reached the quarterfinals of a Grand Slam championship for the first time in her career where she was defeated by top seed, compatriot, and eventual champion, Ashleigh Barty.

[125] Representing Australia at the Tokyo Summer Olympics, Tomljanović defeated in her first round match Kazakh Yaroslava Shvedova who retired due to heat illness.

[126] In November, Tomljanović represented again Australia at the Billie Jean King Cup Finals defeating Aliaksandra Sasnovich in the second tie.

[131] Tomljanović began the clay-court season by making the second round of the Charleston Open where she lost to Irina-Camelia Begu in straight sets.

Tomljanović reached back-to-back quarterfinals at the Wimbledon Championships, defeating Jil Teichmann, Catherine Harrison, Barbora Krejčíková, and Alizé Cornet en route, before losing to eventual champion Elena Rybakina.

[133][134] Tomljanović started the North American hardcourt swing at the Washington Open, losing to eventual champion Liudmila Samsonova in three sets.

Before Australia's tie against British team, Tomljanović announced her withdrawal from her first match against Harriet Dart due to a knee injury.

Two days before the start of the tournament, Tomjlanović again had to withdraw from her home Grand Slam event due to the same lingering knee issue.

Tomljanović returned at the 2023 US Open where she beat Panna Udvardy in three sets but had to withdraw due to fatigue before her second-round match with fourth seed Elena Rybakina.

[147] Given a wildcard into the main draw at the Australian Open,[148] Tomljanović defeated Ashlyn Krueger to reach the second round,[149] where she lost to 12th seed Diana Shnaider.

[citation needed] Tomljanovic made her World TeamTennis debut with the Vegas Rollers during the 2020 WTT season played at The Greenbrier.