| Date: | 22–28 February |
| Edition: | 3rd |
| Surface: | Hard (Indoor) |
| Location: | Nur-Sultan, Kazakhstan |
| Champs: |  Mackenzie McDonald |
| Champd: |  Denys Molchanov /  Aleksandr Nedovyesov |
| After Name: | Nur-Sultan Challenger II |
| After Year: | 2021 |
The 2021 Nur-Sultan Challenger was a professional tennis tournament played on indoor hard courts. It was the third edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Nur-Sultan, Kazakhstan between 22 and 28 February 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Kazakhstan | Mikhail Kukushkin | 90 | 1 | |
 Russian Federation | Evgeny Donskoy | 123 | 2 | |
 India | Prajnesh Gunneswaran | 131 | 4 | |
| Henri Laaksonen | 139 | 5 | ||
 Austria | Jurij Rodionov | 152 | 6 | |
 Slovakia | Martin Kližan | 158 | 7 | |
| Blaž Rola | 159 | 8 |
The following players received wildcards into the singles main draw:
Timofey Skatov Dostanbek Tashbulatov Denis YevseyevThe following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
The following players received entry as lucky losers:
See main article: 2021 Nur-Sultan Challenger – Singles.
Mackenzie McDonald def. Jurij Rodionov 6–1, 6–2.See main article: 2021 Nur-Sultan Challenger – Doubles.
Denys Molchanov / Aleksandr Nedovyesov def. Nathan Pasha / Max Schnur 6–4, 6–4.
