2021 end-of-year rugby union internationals

The 2021 end of year rugby union tests, also referred to as the Autumn internationals in the Northern Hemisphere, were rugby union test matches during October and November 2021, mainly involving countries from the Northern Hemisphere hosting those from the Southern Hemisphere. These international games counted towards World Rugby's ranking system, with teams typically playing from two to four matches in this period.

Matches hosted by teams from the Six Nations Championship were branded the Autumn Nations Series for marketing purposes.