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.

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: