2008 Gerry Weber Open – Singles

Tomáš Berdych was the defending champion, but lost in the second round to Robin Söderling.

Roger Federer won in the final 6–3, 6–4, against Philipp Kohlschreiber. It was Federer's record-extending fifth singles title in Halle, after previously winning four consecutive titles (2003–06) and skipping the tournament in 2007 due to fatigue. He did not lose a single set in the entire tournament and, in the process, extended his record grass court winning streak to 59 matches.

Seeds
• # Roger Federer (champion)

• # 🇺🇸 James Blake (semifinals)

• # 🇨🇿 Tomáš Berdych (second round)

• # 🇷🇺 Mikhail Youzhny (second round)

• # 🇨🇾 Marcos Baghdatis (quarterfinals)

• # 🇨🇿 Radek Štěpánek (first round)

• # 🇫🇮 Jarkko Nieminen (first round)

• # Ivan Ljubičić (first round)