The 2009 Gerry Weber Open was a men's tennis tournament played on outdoor grass courts. It was the 17th edition of the event known that year as the Gerry Weber Open, and was part of the ATP World Tour 250 series of the 2009 ATP World Tour. It took place at the Gerry Weber Stadion in Halle, North Rhine-Westphalia, Germany, from 6 June through 14 June 2009.
The singles draw featured Miami, Monte Carlo and Rome finalist, Dubai and Belgrade titlist Novak Djokovic and 2008 Davis Cup winner, Brisbane runner-up Fernando Verdasco. Also seeded were Johannesburg and Marseille winner Jo-Wilfried Tsonga, Munich champion Tomáš Berdych, Dmitry Tursunov, Jürgen Melzer and Rainer Schüttler. Association of Tennis Professionals (ATP) No. 2 Roger Federer, reigning US Open champion, winner of the Madrid Open and runner-up in the 2009 Australian Open, was initially in the draw as the top seed, but pulled out before playing a match, citing fatigue after winning the French Open the previous week.
The doubles draw was led by 2009 French Open champions, US Open, Rotterdam, and 2008 Halle finalists Lukáš Dlouhý and Leander Paes. Also present were Acapulco winners František Čermák and Michal Mertiňák, Martin Damm and Robert Lindstedt, and Philipp Petzschner and Alexander Peya.
The singles event was won by German Tommy Haas, who had earned a wildcard entry into the main draw, over Djokovic in three sets. The doubles were won by the unseeded German pair of Christopher Kas and Philipp Kohlschreiber in straight sets over the wildcard pair of German Andreas Beck and Swiss Marco Chiudinelli.
See main article: 2009 Gerry Weber Open – Singles. Tommy Haas defeated 
Novak Djokovic, 6–3, 6–7(4–7), 6–1
See main article: 2009 Gerry Weber Open – Doubles. Christopher Kas / Philipp Kohlschreiber defeated Andreas Beck / Marco Chiudinelli, 6–3, 6–4
| Player | Nationality | Ranking* | Seeding | |
|---|---|---|---|---|
| Roger Federer | Switzerland | 2 | 1 | |
| Novak Djokovic | Serbia | 4 | 2 | |
| Fernando Verdasco |  Spain | 8 | 3 | |
| Jo-Wilfried Tsonga |  France | 9 | 4 | |
| Tomáš Berdych |  Czech Republic | 20 | 5 | |
| Dmitry Tursunov |  Russia | 23 | 6 | |
| Jürgen Melzer |  Austria | 26 | 7 | |
| Rainer Schüttler | Germany | 29 | 8 |
The following players received wildcards into the main draw:
The following players received entry from the qualifying draw:
