| Guillermo Balzi | |
| Birth Date: | 23 July 2001 |
| Birth Place: | Los Surgentes, Argentina |
| Height: | 1.75 m |
| Currentclub: | Levadiakos (on loan from Newell's Old Boys) |
| Clubnumber: | 11 |
| Position: | Midfielder |
| Youthclubs1: | Newell's Old Boys |
| Years1: | 2021–2022 |
| Clubs1: | Newell's Old Boys II |
| Years2: | 2022– |
| Clubs2: | Newell's Old Boys |
| Caps2: | 50 |
| Goals2: | 1 |
| Years3: | 2024– |
| Clubs3: | → Levadiakos (loan) |
| Caps3: | 10 |
| Goals3: | 2 |
| Pcupdate: | 30 November 2024 |
Guillermo Balzi (born 23 July 2001) is an Argentine professional footballer who plays as a midfielder for Greek Super League club Levadiakos, on loan from Newell's Old Boys.