2018 Stockholm Open – Singles

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.

Seeds
The top four seeds receive a bye into the second round. • #🇺🇸 John Isner (semifinals)

• #🇮🇹 Fabio Fognini (semifinals)

• # Stefanos Tsitsipas (champion)

• #🇺🇸 Jack Sock (quarterfinals)

• #🇫🇷 Lucas Pouille (first round)

• #🇰🇷 Chung Hyeon (quarterfinals, retired)

• #🇨🇦 Denis Shapovalov (second round)

• #🇪🇸 Fernando Verdasco (second round)

Seeds
• # 🇫🇷 Julien Benneteau (qualifying competition)

• # 🇦🇺 Bernard Tomic (first round, retired)

• # 🇺🇸 Michael Mmoh (first round)

• # 🇨🇦 Peter Polansky (qualified)

• # 🇪🇪 Jürgen Zopp (qualifying competition, lucky loser)

• # 🇩🇪 Matthias Bachinger (qualifying competition)

• # Ernests Gulbis (qualified)

• # 🇩🇪 Mats Moraing (first round)

Qualifiers
• # Ernests Gulbis

• # 🇩🇪 Oscar Otte

• # 🇦🇺 Alexei Popyrin

• # 🇨🇦 Peter Polansky

Lucky loser

 * 1) 🇪🇪 Jürgen Zopp