Poland striker Lewandowski marked his Dortmund farewell with two goals in Saturday's 4-0 hammering of Hertha Berlin in a game that saw Reus hobble off injured 20 minutes from time.
Lewandowski's brace saw him finish as the Bundesliga's top scorer this season and Klopp has backed Reus to follow in the 25-year-old's footsteps.
"Next season it's Marco Reus' turn to finish as Bundesliga top scorer," he said.
Having tucked home a neat first-half goal, Lewandowski scored a stunning free-kick after the break to underline his quality.
Klopp, though, joked that the Pole was rarely a threat from set-pieces.
"He practiced free-kicks for four years. From doing 8,000 in training, no more than three went in - unfortunately this is the truth," he said.
The win set Dortmund up nicely for the DFB-Pokal against Bayern next Saturday and Klopp was pleased to finish five points better off than last season.
He added: "I am extremely satisfied, we have deserved it and pretty much won because we were highly motivated to get to 71 points."
The extent of Reus' injury is yet to be confirmed.
Lewandowski, meanwhile, was "proud" to bring the curtain down on his Dortmund career in style.
"I am very, very proud," he said in quotes reported on the club's official website. "I would like to thank the entire team, because without them I could not have done it.
"I only found out after the game that I won the cannon (top-scorer award). This makes me incredibly happy, it was always my goal to be top scorer."
