The 2019 Sibiu Open was a professional tennis tournament played on clay courts. It was the eighth edition of the tournament which was part of the 2019 ATP Challenger Tour. It took place in Sibiu, Romania between 16 and 22 September 2019.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Pedro Sousa | 123 | 1 | ||
| Blaž Rola | 133 | 2 | ||
 Hungary | ||||
 Spain | Pedro Martínez | 149 | 4 | |
 Serbia | Nikola Milojević | 151 | 5 | |
 Argentina | Federico Coria | 155 | 6 | |
| Robin Haase | 156 | 7 | ||
| Rudolf Molleker | 157 | 8 | ||
| João Domingues | 179 | 9 | ||
| Argentina | Facundo Argüello | 181 | 10 | |
| Tallon Griekspoor | 187 | 11 | ||
 Slovakia | Filip Horanský | 189 | 12 | |
 Kazakhstan | Dmitry Popko | 216 | 13 | |
 Australia | Christopher O'Connell | 223 | 14 | |
| Serbia | Peđa Krstin | 224 | 15 | |
| Spain | Bernabé Zapata Miralles | 236 | 16 |
The following players received wildcards into the singles main draw:
Victor Vlad Cornea
Michał Dembek Alexandru Jecan Filip Cristian JianuThe following players received entry into the singles main draw as alternates:
Pavel Nejedlý Petr Nouza
Fabien ReboulThe following players received entry from the qualifying draw:
The following player received entry as a lucky loser:
See main article: 2019 Sibiu Open – Singles.
Danilo Petrović def. Christopher O'Connell 6–4, 6–2.See main article: 2019 Sibiu Open – Doubles.
Sadio Doumbia / Fabien Reboul def. Ivan Sabanov / Matej Sabanov 6–4, 3–6, [10–7].