The 2021 Queen's Club Championships (also known as the cinch Championships for sponsorship reasons) was a tennis tournament played on outdoor grass courts at the Queen's Club in London, United Kingdom from 14 to 20 June 2021.

[1] It was the 118th edition of the event and part of the ATP Tour 500 series of the 2021 ATP Tour.

*per team The following players received wildcards into the main draw: The following player received entry using a protected ranking: The following players received entry from the qualifying draw: The following player received entry as a lucky loser: The following pairs received wildcards into the doubles main draw: The following pair received entry as an alternate: