The defending champion in the singles was the German Tommy Haas , who was seeded number three this year. He lost in the semifinals to last year's finalist and this year's winner Roger Federer in three sets. He won the final against the Russian Michail Juschny , after losing the starting set, in three sets. With this, Federer ended his lean period of 10 months without a tournament victory on the ATP Tour. The last time he left the tournament as a tournament winner was in August 2012 when he won the title at the Cincinnati Masters . At the Gerry Weber Open, he took his sixth victory in his eighth finals. Aisam-ul-Haq Qureshi and Jean-Julien Rojer defended their title in doubles, but were eliminated in the first round against Kei Nishikori and Milos Raonic . This year's event won Santiago González and Scott Lipsky in two sets against Daniele Bracciali and Jonathan Erlich .
The field of participants in the single competition consisted of 28 players, that of the doubles competition consisted of 16 pairs. The four top seeded players each received a bye into the second round.
The qualification for the Gerry Weber Open 2013 took place on June 8th and 9th, 2013. Four qualifying places were played that entitle them to participate in the main draw of the tournament.
At the Gerry Weber Open 2013, the following prize money and world ranking points were paid out or credited for reaching the respective round. Players who entered the main field from qualification received the specified qualification points in addition to those for reaching the respective round. Otherwise the amounts are not to be understood as cumulative. The amounts for the double competition were per player.