List of number-one singles of 2021 (Australia)

This is a list of singles that reached number one on the Australian Recording Industry Association (ARIA) singles chart during 2021. The ARIA chart ranks the best-performing singles in Australia and is based on both physical sales and digital downloads, as well as streaming data.

The listing typically includes the artist(s) who performed the song, the title of the song, and the date on which it first reached the number one position. It may also include the number of weeks the song spent at the top of the chart.

Information about specific artists, songs, and their chart performance during 2021 can be found on the ARIA website and in other music publications. Detailed chart histories for previous years are also available through similar resources. The chart week typically runs from Friday to Thursday, with the new chart published on Friday.