| Date: | 24 – 31 July |
| Edition: | 77th |
| Category: | World Tour 250 series |
| Surface: | Clay / Outdoor |
| Location: | Kitzbühel, Austria |
| Venue: | Tennis stadium Kitzbühel |
| Champs: |  Casper Ruud |
| Champd: |  Alexander Erler / Lucas Miedler |
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]
See main article: 2021 Generali Open Kitzbühel – Singles.
Casper Ruud def. 
Pedro Martínez, 6–1, 4–6, 6–3.See main article: 2021 Generali Open Kitzbühel – Doubles.
Alexander Erler / Lucas Miedler def. 
Roman Jebavý / Matwé Middelkoop, 7–5, 7–6(7–5)| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q | width=85 | Q2 | width=85 | Q1 |
| Singles | 250 | 150 | 90 | 45 | 20 | 0 | 12 | 6 | 0 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubles | 0 |
| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q2 | width=85 | Q1 |
| Singles | €41,145 | €29,500 | €21,000 | €14,000 | €9,000 | €5,415 | €2,645 | €1,375 | ||
| Doubles* | €15,360 | €11,000 | €7,250 | €4,710 | €2,760 |
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Norway | Casper Ruud | 14 | 1 | |
| Spain | Roberto Bautista Agut | 16 | 2 | |
 Serbia | Filip Krajinović | 34 | 3 | |
| Spain | Albert Ramos Viñolas | 43 | 4 | |
 Argentina | Federico Delbonis | 46 | 5 | |
| Serbia | Laslo Đere | 52 | 6 | |
 France | ||||
| Spain | Jaume Munar | 67 | 9 | |
| Spain | Carlos Alcaraz | 73 | 10 |
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:
Carlos Taberner Richard Gasquet → replaced by Mario Vilella Martínez Dušan Lajović → replaced by Arthur Rinderknech Corentin Moutet → replaced by 
Mikael Ymer
Lorenzo Musetti → replaced by 
Radu Albot Jo-Wilfried Tsonga → replaced by Lucas Pouille| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
 Bosnia and Herzegovina | Tomislav Brkić | Serbia | Nikola Ćaćić | 99 | 1 | |
| Hugo Nys | Italy | Andrea Vavassori | 131 | 2 | ||
| Czech Republic | Roman Jebavý | Matwé Middelkoop | 147 | 3 | ||
| Ariel Behar | Argentina | Guillermo Durán | 166 | 4 |
The following pairs received wildcards into the doubles main draw:
The following pair received entry using a protected ranking:
Arthur Rinderknech
Gonzalo Escobar → replaced by Ariel Behar / Guillermo Durán Fabrice Martin → replaced by Pablo Cuevas / 
Thiago Seyboth Wild