The Women's National Basketball Association (WNBA) is a professional women's basketball league based in the United States with 12 teams as of 2024[update].[1] The league was founded in 1996 by the men's National Basketball Association (NBA) as a wholly-owned subsidiary and began play in the 1997 season with eight teams.[2][3] WNBA shares the same court dimensions, hoop height, and shot clock length as NBA, but has had shorter quarters of ten minutes each since 2006 and uses a smaller ball to match with international FIBA standards.[1][4][5] Full NBA ownership of the league ended in 2002 and new independent ownership groups began investing in franchises; the WNBA has seven teams with independent ownership and five that are under the same ownership as an NBA team and share the same home arena.[3][6]
The league's 12 teams are organized into the Eastern and Western conferences;[1] a 13th team is scheduled to begin play in the 2025 season.[7] The number of WNBA teams has varied since the league's original eight in 1997 due to expansions and later contractions; the first expansion teams were added in 1998 and were followed by two more rounds of additions that brought the total to 16 teams in 2000. Following the change in NBA ownership in 2002, the WNBA lost two teams. The league lost two more teams by 2006 but expanded to remain at 13 teams. The number of teams has remained at 12 since the Houston Comets ceased operations after the 2008 season.[8]
As of the 28th season in 2024, each team plays 40 games during the regular season, which runs from May to September. The 2024 season includes a month-long break for the Summer Olympic Games that begins after the annual WNBA All-Star Game in mid-July.[9][10] The summer schedule is mostly played during the NBA offseason, which allows teams to share venues;[11] during the WNBA offseason, many players transfer to overseas leagues that follow a fall and winter schedule.[12] Teams play four games against opponents in the same conference and two teams from the other conference; three games are played against the remaining four teams in the other conference.[13] Five regular season games in early June are played against teams in the same conference to determine qualification for the WNBA Commissioner's Cup, an in-season tournament first played in 2021; the final is hosted by the team with the better win–loss record in qualifying games.[14]
The eight teams with the best regular season records, regardless of conference, qualify for the WNBA playoffs to determine the league's champion in the WNBA Finals. Since 2022, the playoffs have used a best-of-three series in the first round, where teams are seeded based on regular season performance, and a best-of-five format for the semifinals and WNBA Finals.[15][16] The most successful playoff teams are the Minnesota Lynx, Seattle Storm, and defunct Houston Comets, who have each won four WNBA championships; the Lynx have made six appearances in the WNBA Finals, the most in league history.[17][18] Three current WNBA teams have yet to win a championship; among them, the Connecticut Sun has finished as runners-up in four WNBA Finals.[19]
The best regular season performance in league history was set in the 1998 season by the Houston Comets, who finished with a 27–3 win–loss record—a winning percentage of 0.900. The number of games played by WNBA teams has steadily increased since the initial 28-game schedule in the inaugural season; for most of the league's history, teams played 34 games before the schedule was expanded to 36 games in 2022 and 40 games in 2023. The Las Vegas Aces won 34 games during the expanded 2023 season and set a record for most wins in a WNBA season.[20][21] The WNBA playoffs has also changed its format several times; until 2016, the two conferences were separated until the WNBA Finals. Under the cross-conference format, top-seeded teams received single or double byes and some rounds had single-elimination games instead of a best-of-five series.[22] The format was simplified in 2022 to remove single-elimination rounds and byes.[16]