| Date: | 12–18 July |
| Edition: | 2nd |
| Draw: | 32S / 16D |
| Surface: | Clay |
| Location: | Iași, Romania |
| Champs: |  Zdeněk Kolář |
| Champd: |  Orlando Luz / Felipe Meligeni Alves |
The 2021 Iași Open was a professional tennis tournament played on clay courts. It was the second edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Iași, Romania between 12 and 18 July 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 France | Hugo Gaston | 162 | 1 | |
| France | Enzo Couacaud | 164 | 2 | |
| France | Alexandre Müller | 199 | 3 | |
| Brazil | Felipe Meligeni Alves | 221 | 4 | |
| Czech Republic | Zdeněk Kolář | 223 | 5 | |
 Romania | Marius Copil | 224 | 6 | |
| France | Maxime Janvier | 232 | 7 | |
| Dimitar Kuzmanov | 246 | 8 |
The following players received wildcards into the singles main draw:
Cezar Crețu David Ionel Ștefan PaloșiThe following player received entry into the singles main draw using a protected ranking:
The following player received entry into the singles main draw as an alternate:
The following players received entry from the qualifying draw:
David Poljak Dan Alexandru Tomescu
Miljan ZekićThe following player received entry as a lucky loser:
See main article: 2021 Iași Open – Singles.
Zdeněk Kolář def. Hugo Gaston 7–5, 4–6, 6–4.See main article: 2021 Iași Open – Doubles.
Orlando Luz / Felipe Meligeni Alves def. 
Hernán Casanova / 
Roberto Ortega Olmedo 6–3, 6–4.
