2015 Citi Open – Men's singles

Milos Raonic was the defending champion, but chose not to participate this year.

Kei Nishikori won the title, defeating John Isner in the final, 4–6, 6–4, 6–4.

Seeds
All seeds receive a bye into the second round. • 🇬🇧 Andy Murray (second round)

• 🇯🇵 Kei Nishikori (champion)

• Marin Čilić (semifinals)

• 🇫🇷 Richard Gasquet (third round)

• Kevin Anderson (second round)

• 🇧🇬 Grigor Dimitrov (third round)

• 🇪🇸 Feliciano López (third round)

• 🇺🇸 John Isner (final)

• 🇷🇸 Viktor Troicki (second round)

• Ivo Karlović (second round)

• 🇦🇺 Bernard Tomic (second round)

• 🇨🇦 Vasek Pospisil (third round)

• 🇺🇸 Sam Querrey (third round)

• Pablo Cuevas (second round)

• 🇺🇸 Jack Sock (quarterfinals)

• 🇦🇷 Leonardo Mayer (third round)

Seeds
• # 🇺🇸 Rajeev Ram (withdrew)

• # 🇬🇧 Kyle Edmund (first round)

• # Ivan Dodig (qualifying competition, lucky loser)

• # 🇬🇧 James Ward (first round)

• # 🇦🇷 Guido Pella (qualified)

• # 🇨🇴 Alejandro González (qualifying competition)

• # 🇺🇸 Ryan Harrison (qualified)

• # 🇺🇸 Austin Krajicek (first round)

• # 🇦🇺 John-Patrick Smith (qualified)

• # 🇯🇵 Yoshihito Nishioka (qualified)

• # 🇮🇳 Somdev Devvarman (first round)

• # 🇯🇵 Yūichi Sugita (first round)

Qualifiers
• # 🇦🇺 Marinko Matosevic

• # 🇺🇸 Ryan Harrison

• # 🇯🇵 Yoshihito Nishioka

• # Darian King

• # 🇦🇷 Guido Pella

• # 🇦🇺 John-Patrick Smith

Lucky losers

 * 1)  Ivan Dodig