A-League Women (currently known as the Ninja A-League for sponsorship reasons), formerly the W-League, is the top-division women's soccer league in Australia. The W-League was established in 2008 by Football Australia (then known as Football Federation Australia) and was originally composed of eight teams of which seven had an affiliation with an existing A-League Men's club. As of the 2022–23 season, the league is contested by twelve teams. The league, as well as the A-League Men and A-League Youth are administered by the Australian Professional Leagues.
Seasons now run from November to April and include a 23-round regular season and an end-of-season finals series playoff tournament involving the highest-placed teams, culminating in a Grand Final match. The winner of the regular season tournament is dubbed "premiers" and the winner of the grand final is dubbed "champions". The premiers qualify for the AFC Women's Champions League, starting from the 2024–25 season.
Since the league's inaugural season, a total of five clubs have been crowned premiers and five clubs have been crowned champions. It has been currently running on a semi-professional basis, but talks about professionalisation have been emerging, beginning with the name change and placing of all women's clubs into one single Australian Professional Leagues operation and management in 2021, which served as the precursors for complete transition to professionalism of the A-League Women.
Melbourne City are the current premiers, having won their third title; Sydney FC are the current champions, having won their fifth title.
Between 1996 and 2004 the Women's National Soccer League (WNSL) was Australia's top women's soccer league. In 2004 it was discontinued alongside the men's National Soccer League.
After Australia qualified for the quarter-finals of the 2007 FIFA Women's World Cup, head coach Tom Sermanni felt the establishment of a professional league was vital for continuing the development of players. Football Federation Australia established the league the following year. The W-League was initially composed of eight teams: Adelaide United, Brisbane Roar, Central Coast Mariners, Melbourne Victory, Newcastle Jets, Perth Glory, and Sydney FC. Seven of the eight teams were affiliated with A-League clubs, and shared their names and colours to promote their brands. The eighth club was Canberra United.
The W-League's inaugural season commenced on 25 October 2008, with Perth hosting Sydney at Members Equity Stadium. After ten rounds, the regular season finished with Queensland Roar as the top-placed team, becoming the first W-League premiers, and advancing to the semi-finals along with the second-, third- and fourth-placed teams. Queensland faced Canberra in the 2009 W-League grand final, defeating them 2–0 to take the champions trophy.
Central Coast Mariners were forced to withdraw from the 2010–11 season due to a lack of funding, but returned in 2023–24.
When Western Sydney Wanderers joined the A-League for the 2012–13 season, they also entered a team into the W-League, returning the competition to eight teams. From 2012 to 2014, the W-League champion team qualified into an international competition, the International Women's Club Championship.
On 13 May 2015, Melbourne City were confirmed to compete in the W-League from the 2015–16 season. The club had a remarkable inaugural season, winning all 12 of its regular season games and winning the Grand Final.
From the inception of the competition the league was run by Football Federation Australia, the governing body for the sport in Australia. In July 2019, the FFA relinquished operational control of the league to each of the clubs, now represented by the Australian Professional Leagues.
The league commenced a further expansion program starting in 2021, with Wellington Phoenix commencing in the 2021–22 season, Western United for the 2022–23 season, and Central Coast Mariners for the 2023–24 season. Future expansion is planned for the 2025–26 season, after the award of a licence for an Auckland-based team for both A-League Men and Women.
Crowds have improved remarkably in 2023, on the back of the Matildas performance in the 2023 FIFA Women's World Cup. The record A-League Women's crowd (including finals) was set on 14 October 2023, with the match between Sydney FC and the Western Sydney Wanderers drawing a crowd of 11,471.
Around 15 April 2024, the 2023–24 A-League Women season become the most attended season of any women's sport in Australian history by recording a total attendance of 284,551; the season finished with a final total attendance of 312,199.