The 2020 Sibiu Open was a professional tennis tournament played on clay courts. It was the ninth edition of the tournament which was part of the 2020 ATP Challenger Tour. It took place in Sibiu, Romania between 21 and 27 September 2020.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 France | Arthur Rinderknech | 163 | 1 | |
| France | Quentin Halys | 200 | 2 | |
| Marc-Andrea Hüsler | 218 | 3 | ||
 Argentina | Francisco Cerúndolo | 237 | 4 | |
 Russian Federation | Evgeny Karlovskiy | 254 | 5 | |
 Spain | Adrián Menéndez Maceiras | 262 | 6 | |
 Tunisia | Malek Jaziri | 264 | 7 | |
 Japan | Shuichi Sekiguchi | 274 | 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 player received entry into the singles main draw as an alternate:
The following players received entry from the qualifying draw:
Carlos Gómez-Herrera
Ergi Kırkın Matthieu PerchicotSee main article: 2020 Sibiu Open – Singles.
Tomás Martín Etcheverry 7–5, 6–0.See main article: 2020 Sibiu Open – Doubles.
Hunter Reese / 
Jan Zieliński def. Robert Galloway / 
Hans Hach Verdugo 6–4, 6–2.
