The 2021 Generali Open Kitzbühel is a tennis tournament played on outdoor clay courts.

It is the 77th edition of the Austrian Open Kitzbühel, and part of the World Tour 250 series of the 2021 ATP Tour.

It will take place at the Tennis stadium Kitzbühel in Kitzbühel, Austria, from 24 through 31 July 2021.

[1] *per team The following players received wildcards into the singles main draw: The following player received entry as an alternate: The following player received entry as a special exempt: The following players received entry from the qualifying draw: The following players received entry as lucky losers: The following pairs received wildcards into the doubles main draw: The following pair received entry using a protected ranking: