The 2020–21 A-League was the 44th season of national level soccer in Australia, and the 16th since the establishment of the A-League in 2004. The season was started on 28 December 2020 and concluded with the Grand Final on 27 June 2021. The start of the season was later than previous seasons as a result of both the COVID-19 pandemic in Australia and New Zealand, and as part of a gradual shift to move the competition from summer to winter. Wellington Phoenix played the majority of their home matches at Wollongong Showground in Wollongong due to international travel restrictions.

A-League Men is the highest-level professional men's soccer league in Australia and New Zealand. At the top of the Australian league system, it is the country's premier men's competition for the sport. A-League Men was established in 2004 as the A-League by the Football Federation Australia (FFA) as a successor to the National Soccer League (NSL) and competition commenced in August 2005. The league is currently administered by the Australian Professional Leagues (APL), contested by twelve teams; eleven based in Australia and one based in New Zealand. The men's, women's and youth leagues have now been brought together under a unified A-Leagues banner.