[1] It was the 29th annual countdown of the most popular songs of the year, as voted for by listeners of Australian radio station triple j. Australian children's music group the Wiggles was voted into first place with their Like a Version cover of Tame Impala's "Elephant", making it the first Like a Version to place first in a Hottest 100.

Olivia Rodrigo and Doja Cat achieved the most entries in the countdown, with both scoring five.

[2] On 18 March 2022, triple j confirmed that a compilation album would no longer be released in conjunction with the annual countdown.

Any song initially released between 1 December 2020 and 30 November 2021 was eligible for the 2021 triple j Hottest 100.

Various music blogs and bookmakers placed "Stay" by Australian rapper the Kid Laroi and Canadian musician Justin Bieber; "Good 4 U" by American singer Olivia Rodrigo; "The Angel of 8th Ave." by Australian rock band Gang of Youths; and Australian children's music group the Wiggles' Like a Version cover of "Elephant" by Tame Impala as the songs most likely to take first place.