The deal to take the 20-year-old to the Bay Arena is reportedly worth up to £11m.
Frimpong joined Celtic from Manchester City in the summer of 2019 for £300,000 and made 36 league appearances for The Bhoys in his season-and-a-half stay, scoring three goals.
"Bayer 04 have signed the Dutch right-back Jeremie Frimpong. The Holland U20 international joins the Werkself from Scottish champions Celtic. The 20-year-old has signed a contract at Leverkusen to 30 June 2025," Leverkusen announced on their official website.
Frimpong is still eligible to play for Ghana at international level from his mother’s side.
"Great opportunity to be able to play in one of the best leagues in Europe," Frimpong said on his move.
"I'm totally looking forward to the Bundesliga and, of course, this club in particular. Bayer 04 Leverkusen have regularly been in the Champions League and the Europa League.
"They demonstrated their ambition on the European stage last year in the two games against Glasgow Rangers.
"I really like the offensive, fast and technical style of play at Bayer 04 and I hope I can soon help the team."
"In Jeremie Frimpong, we have been able to sign a player with a great facility to develop and this again is a forward-looking transfer for Bayer 04. He's technically strong, incredibly quick and has the desire to go forwards," club sporting director Simon Rolfes added.
"Over the last year and a half, Jeremie has proved himself at an absolute top club in the physically very challenging Scottish league and in European competition.
"That important experience at Celtic, but above all his footballing ability, make him a very attractive young player."
