The manager is confident that last year's Champions League finalists will overcome the attacker's exit.
The Bavarians announced Saturday that the Poland international had signed a five-year deal with his new club, but Klopp is not too bothered by Lewandowski's imminent departure.
"Players can always be bought by other teams, but the club Borussia Dortmund are bigger than any player. It's all about having a good plan for the future. Things will go on, I have no doubt about that," Klopp said at a press conference. "Robert's decision is perfectly fine with us. We knew about his decision to leave for quite some time. Robert has never looked as if he wasn't focused on Dortmund. That his next club is official now is perfect timing. There would only have been a lof of speculation otherwise."
Lewandowski himself, meanwhile, has made it clear that he will continue to give his all for BVB.
"Dear BVB fans, I would like to say a few words to you," an open letter on the Dortmund website reads. "With half a year to go, there are still some goals we want to achieve together. I hope you will support me, even if some of you don’t agree with my decision! I for one will give my all for BVB!
"Yours, Robert Lewandowski."
The 25-year-old has scored 11 goals in 17 league appearances so far this season.