| Date: | 20–26 September |
| Edition: | 1st |
| Surface: | Clay |
| Location: | Bucharest, Romania |
| Champs: |  Jiří Lehečka |
| Champd: | Ruben Gonzales /  Hunter Johnson |
The 2021 Bucharest Challenger was a professional tennis tournament played on clay courts. It was the 1st edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Bucharest, Romania between 20 and 26 September 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Italy | Stefano Travaglia | 99 | 1 | |
 Moldova, Republic of | Radu Albot | 105 | 2 | |
 Australia | Thanasi Kokkinakis | 180 | 3 | |
| Czech Republic | Zdeněk Kolář | 185 | 4 | |
 India | Sumit Nagal | 186 | 5 | |
| Maximilian Marterer | 197 | 6 | ||
| Czech Republic | Vít Kopřiva | 198 | 7 | |
| Czech Republic | Jiří Lehečka | 201 | 8 |
The following players received wildcards into the singles main draw:
Nicolae Frunză David Ionel Ștefan PaloșiThe following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
See main article: 2021 Bucharest Challenger – Singles.
Jiří Lehečka def. 
Filip Horanský 6–3, 6–2.See main article: 2021 Bucharest Challenger – Doubles.
Hunter Johnson def. Maximilian Marterer / Lukáš Rosol 1–6, 6–2, [10–3].
