| 2021 Biella Challenger Indoor IV | |
|---|---|
| Date | 15–21 March |
| Edition | 4th |
| Draw | 32S / 16D |
| Surface | Hard (indoor) |
| Location | Biella, Italy |
| Champions | |
| Singles | |
 Daniel Masur | |
| Doubles | |
 Lloyd Glasspool /  Matt Reid | |
The 2021 Biella Challenger Indoor IV was a professional tennis tournament played on hard courts. It was the 4th edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Biella, Italy between 15 and 21 March 2021.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
 FRA | Lucas Pouille | 81 | 1 |
| GER | Yannick Hanfmann | 105 | 2 |
 ITA | Andreas Seppi | 107 | 3 |
 JPN | Yūichi Sugita | 108 | 4 |
| JPN | Yasutaka Uchiyama | 109 | 5 |
 BLR | Ilya Ivashka | 113 | 6 |
| FRA | Grégoire Barrère | 115 | 7 |
| FRA | Benjamin Bonzi | 127 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw using a protected ranking:
The 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:
Daniel Masur def. Matthias Bachinger 6–3, 6–7(8–10), 7–5. Lloyd Glasspool / Matt Reid def. 
Denys Molchanov / Sergiy Stakhovsky 6–3, 6–4.
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