Arsenal manager Unai Emery has described new signing Bernd Leno as possessing "high quality and experience".
The German goalkeeper has agreed to join the North London outfit, but the length of contract is unknown.
The 26-year-old, who joined Bayer Leverkusen in 2011 from Stuttgart, is expected to challenge Petr Cech for the number one spot.
"We are very pleased that Bernd Leno will be joining us," Emery told Arsenal's official website. "Bernd is a goalkeeper of high quality and experience.
"He has been a top performer and regular number one goalkeeper with Leverkusen in the Bundesliga for the past seven years. We are all excited that Bernd has chosen Arsenal Football Club and look forward to start working with him in pre-season."
Leno follows Stephan Lichtsteiner as Emery's second signing of the summer since being appointed Arsenal boss.
