| 2021 Nur-Sultan Challenger II | |
|---|---|
| Date | 1–8 March |
| Edition | 4th |
| Surface | Hard (indoor) |
| Location | Nur-Sultan, Kazakhstan |
| Champions | |
| Singles | |
 Tomáš Macháč | |
| Doubles | |
 Nathaniel Lammons / Jackson Withrow | |
The 2021 Nur-Sultan Challenger II was a professional tennis tournament played on indoor hard courts. It was the fourth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Nur-Sultan, Kazakhstan between 1 and 7 March 2021.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
 KOR | Kwon Soon-woo | 81 | 1 |
 FIN | Emil Ruusuvuori | 85 | 2 |
 KAZ | Mikhail Kukushkin | 94 | 3 |
 AUS | James Duckworth | 100 | 4 |
 JPN | Taro Daniel | 120 | 5 |
 RUS | Evgeny Donskoy | 123 | 6 |
 SUI | Henri Laaksonen | 134 | 7 |
 IND | Prajnesh Gunneswaran | 138 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
The following players received entry as lucky losers:
Tomáš Macháč def. 
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