| Date: | 1 – 7 March |
| Edition: | 24th |
| Category: | ATP Tour 250 series |
| Prize Money: | $411,940 |
| Draw: | 28S / 16D |
| Surface: | Clay / outdoor |
| Location: | Buenos Aires, Argentina |
| Venue: | Buenos Aires Lawn Tennis Club |
| Champs: |  Diego Schwartzman |
| Champd: |  Tomislav Brkić /  Nikola Ćaćić |
| Main Name: | ATP Buenos Aires |
The 2021 Argentina Open was a men's tennis tournament played on outdoor clay courts. It was the 24th edition of the ATP Buenos Aires event and part of the ATP Tour 250 series of the 2021 ATP Tour. It took place in Buenos Aires, Argentina, from 1–7 March 2021.[1]
See main article: 2021 Argentina Open – Singles.
Diego Schwartzman defeated Francisco Cerúndolo, 6–1, 6–2.See main article: 2021 Argentina Open – Doubles.
Tomislav Brkić / Nikola Ćaćić defeated Ariel Behar / 
Gonzalo Escobar, 6–3, 7–5.| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q | width=85 | Q3 | width=85 | Q2 | width=85 | Q1 |
| Singles | 250 | 150 | 90 | 45 | 20 | 0 | 12 | 6 | 3 | 0 | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubles | 0 |
| Event | W | F | SF | QF | Round of 16 | Round of 32 | width=85 | Q3 | width=85 | Q2 | width=85 | Q1 |
| Singles | $24,400 | $18,030 | $13,510 | $9,240 | $6,310 | $4,505 | $3,470 | $2,310 | $1,275 | |||
| Doubles | $8,510 | $6,230 | $4,730 | $3,390 | $2,480 | |||||||
| Doubles prize money per team | ||||||||||||
| width=70 | Country | width=175 | Player | Rank1 | Seed |
|---|---|---|---|---|---|
| Argentina | Diego Schwartzman | 9 | 1 | ||
| Cristian Garín | 22 | 2 | |||
 France | Benoît Paire | 29 | 3 | ||
| Serbia | Miomir Kecmanović | 41 | 4 | ||
 Spain | Albert Ramos Viñolas | 47 | 5 | ||
| Spain | Pablo Andújar | 55 | 6 | ||
| Serbia | Laslo Đere | 59 | 7 | ||
 United States | Frances Tiafoe | 62 | 8 |
The following players received wildcards into the singles main draw:
The following players received special exemptions into the singles main draw:
The following players received entry from the qualifying draw:
Gianluca Mager Pedro Martínez → replaced by 
Andrej Martin Guido Pella → replaced by Roberto Carballés Baena| Country | Player | Country | Player | Rank1 | Seed | |
|---|---|---|---|---|---|---|
| United States | Austin Krajicek | Franko Škugor | 74 | 1 | ||
 Brazil | Marcelo Demoliner |  Mexico | Santiago González | 93 | 2 | |
| Italy | Simone Bolelli | Argentina | Máximo González | 115 | 3 | |
| Ariel Behar | Ecuador | Gonzalo Escobar | 123 | 4 |
The following pairs received wildcards into the doubles main draw:
Marco Cecchinato / Guido Pella → replaced by Roberto Carballes Baena / Salvatore Caruso
Oliver Marach → replaced by Oliver Marach / 
Luis David Martínez Pablo Andújar / Pedro Martinez → replaced by Pablo Andújar / Jaume Munar
