2025 National Bank Open – Men's singles
Ben Shelton defeated Karen Khachanov in the final, 6–7, 6–4, 7–6 to win the men's singles tennis title at the 2025 Canadian Open. It was his first ATP Masters 1000 title and third career ATP Tour title. Shelton was the youngest American man to win a Masters title since Andy Roddick at the 2004 Miami Open.
Alexei Popyrin was the defending champion, but lost in the quarterfinals to Alexander Zverev.
By reaching his first ATP 1000 final since the 2018 Paris Masters, Khachanov recorded the longest gap between successive ATP 1000 finals appearances, at 6 years and 9 months. With his third-round win, Zverev became the first man born in the 1990s to win 500 ATP Tour level main-draw singles matches, and the fifth active player to do so. Taylor Fritz became the first American man to reach the quarterfinals at all nine ATP 1000 tournaments.
This event marked the final professional appearance of former Davis Cup and Wimbledon doubles champion, Vasek Pospisil. He lost in the first round to Facundo Bagnis.
Seeds
All seeds received a bye into the second round.Alexander Zverev '
Taylor Fritz '
Lorenzo Musetti '
Ben Shelton
Holger Rune '
Andrey Rublev '
Frances Tiafoe '
Casper Ruud '
Alex de Minaur '
Daniil Medvedev '
Karen Khachanov '
Jakub Menšík '
Flavio Cobolli '
Francisco Cerúndolo '
Arthur Fils '
Tomáš Macháč '
Ugo Humbert '
Alexei Popyrin '
Jiří Lehečka '
Alejandro Davidovich Fokina '
Félix Auger-Aliassime '
Denis Shapovalov '
Stefanos Tsitsipas '
Tallon Griekspoor '
Brandon Nakashima '
Alex Michelsen '
Gabriel Diallo '
Lorenzo Sonego '
Alexandre Müller '
Nuno Borges '
Cameron Norrie '
Matteo Arnaldi ''''
Draw
Finals
Seeded players
The following are the seeded players. Seedings are based on ATP rankings as of 21 July 2025. Rankings and points before are as of 28 July 2025.Unlike the WTA, the ATP will only drop points from the week of 29 July 2024 during this year's National Bank Open and backdate the ranking points at the end of the tournament to 4 August 2025. Points from the 2024 National Bank Open held in Montreal will be dropped at the end of the 2025 Cincinnati Open instead. Accordingly, the Points Defending column in the table below reflects the 19th best result of players who are not defending points from Washington.
| Seed | Rank | Player | Points before | Points defending | Points earned | Points after | Status | |||
| 1 | 3 |  flagicon|Withdrawn seeded playersThe following players would have been seeded, but withdrew before the tournament began.
|
