| Champ: | Stefanos Tsitsipas |
| Runner: | Ernests Gulbis |
| Score: | 6–4, 6–4 |
| Draw: | 28 |
| Seeds: | 8 |
| Type: | singles doubles |
See main article: 2018 Stockholm Open.
Juan Martín del Potro was the two-time defending champion but chose not to defend his title.
Stefanos Tsitsipas won his first ATP World Tour title, defeating Ernests Gulbis in the final, 6–4, 6–4. With the win, he became the first Greek player to win an ATP title in the organization's 48-year history. Gulbis lost his first ATP Tour final, after six singles titles in a row.
The top four seeds receive a bye into the second round.
