The Welsh man has spent over a decade with the Gunners since being signed by Wenger, helping Arsenal to three FA Cup titles.
The 28-year-old hoped to sign a new deal at Arsenal at the end of last year, but the club decided to withdraw their contract offer.
He has however agreed to join the Serie A champions in a lucrative deal.
Speaking at the Laureus Sport for Good presentation, Wenger admitted it would be a great loss to the North London team.
“It will be a loss for Arsenal.
“I must say it will be an interesting move for Ramsey. He is a player who is great going forward,” Wenger said.
“His main quality is he can keep the final ball. And he makes interesting runs from deep.
“You don’t find many players today who can make midfield runs off the ball. It will be an interesting addition for Juventus.”