The 2021 Biella Challenger VI was a professional tennis tournament played on outdoor red clay courts. It was part of the 2021 ATP Challenger Tour. It took in Biella, Italy between 17 and 23 May 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Italy | Paolo Lorenzi | 167 | 1 | |
 China | Zhang Zhizhen | 183 | 2 | |
 France | Enzo Couacaud | 188 | 3 | |
| France | Alexandre Müller | 189 | 4 | |
 Kazakhstan | Dmitry Popko | 193 | 5 | |
 Australia | Alex Bolt | 194 | 6 | |
 Brazil | João Menezes | 196 | 7 | |
| Bjorn Fratangelo | 198 | 8 |
The following players received wildcards into the singles main draw:
The following players received entry from the qualifying draw:
Riccardo Bonadio
Tomás Martín Etcheverry Omar GiacaloneSee main article: 2021 Biella Challenger VI – Singles.
Thanasi Kokkinakis def. Enzo Couacaud 6–3, 6–4.See main article: 2021 Biella Challenger VI – Doubles.
Evan King / Julian Lenz def. 
Karol Drzewiecki / 
Sergio Martos Gornés 3–6, 6–3, [11–9].