| Champ: |  Benoît Paire |
| Runner: |  Félix Auger-Aliassime |
| Score: | 6–4, 6–3 |
| Draw: | 28 (4 / 3) |
| Seeds: | 8 |
| Edition: | 3rd |
| Type: | singles doubles |
| Main Name: | ATP Lyon Open |
| Before Name: | Lyon Open – Singles |
| After Year: | 2021 |
See main article: 2019 ATP Lyon Open. Dominic Thiem was the defending champion, but he chose not to defend his title this year.
Benoît Paire won the title, defeating Félix Auger-Aliassime in the final, 6–4, 6–3.
The top four seeds receive a bye into the second round.