2012 Western & Southern Open – Men's singles

Roger Federer defeated Novak Djokovic in the final, 6–0, 7–6 (9–7) to win the men's singles tennis title at the 2012 Cincinnati Masters. It was his record fifth Cincinnati Masters title, and the first time that a player won an ATP Tour Masters 1000 event without having his serve broken or losing a set. Federer would repeat this accomplishment at the 2015 event. It was Djokovic's fourth runner-up finish at the tournament.

Andy Murray was the defending champion, but lost in the third round to Jérémy Chardy.

Seeds
The top eight seeds receive a bye into the second round. • # Roger Federer (champion)

• # 🇷🇸 Novak Djokovic (final)

• # 🇬🇧 Andy Murray (third round)

• # 🇪🇸 David Ferrer (second round)

• # 🇨🇿 Tomáš Berdych (third round)

• # 🇦🇷 Juan Martín del Potro (semifinals)

• # 🇷🇸 Janko Tipsarević (second round, retired because of a virus)

• # 🇦🇷 Juan Mónaco (second round)

• # 🇺🇸 John Isner (withdrew because of a back injury)

• # 🇺🇸 Mardy Fish (quarterfinals)

• # 🇫🇷 Gilles Simon (withdrew because of a shoulder injury)

• # Marin Čilić (quarterfinals)

• # 🇺🇦 Alexandr Dolgopolov (first round)

• # 🇯🇵 Kei Nishikori (third round)

• # 🇩🇪 Philipp Kohlschreiber (first round)

• # 🇺🇸 Andy Roddick (first round)

Seeds
• # 🇫🇷 Jérémy Chardy (qualifying competition, lucky loser)

• # 🇨🇴 Alejandro Falla (qualifying competition, lucky loser)

• # 🇧🇬 Grigor Dimitrov (first round)

• # 🇸🇰 Lukáš Lacko (first round)

• # 🇧🇪 David Goffin (qualifying competition)

• # 🇦🇺 Marinko Matosevic (qualified)

• # 🇦🇷 Leonardo Mayer (qualifying competition)

• # 🇮🇹 Fabio Fognini (qualified)

• # 🇰🇿 Mikhail Kukushkin (withdrew because of a hip injury)

• # Lu Yen-hsun (qualified)

• # Igor Sijsling (first round)

• # 🇧🇪 Steve Darcis (first round)

• # 🇦🇺 Matthew Ebden (first round)

• # 🇩🇪 Philipp Petzschner (first round)

Qualifiers
• # 🇮🇹 Fabio Fognini

• # Lu Yen-hsun

• # 🇫🇷 Paul-Henri Mathieu

• # 🇺🇸 Jesse Levine

• # Ivan Dodig

• # 🇦🇺 Marinko Matosevic

• # 🇺🇦 Sergiy Stakhovsky

Lucky losers

 * 1) 🇫🇷 Jérémy Chardy
 * 2) 🇨🇴 Alejandro Falla