Schick still had three years remaining on his previous deal.
The 26-year-old Czech Republic international joined Leverkusen from AS Roma in the summer of 2020.
He emerged as the second top scorer behind Robert Lewandowski in the German Bundesliga this season, scoring 24 goals in 27 games as Leverkusen finished in third position and qualified for the Champions League.
Schick had been linked with a move to the Premier League after his impressive season but is delighted to stay put in Germany.
"I just feel good here, but above all, our team has promise for the future. It's a lot of fun with these guys," the former RB Leipzig striker said of his extension.
"Qualifying for the Champions League is a good next step. A lot is possible here, which is exactly why I extended my contract at Bayer 04."
"For me, Patrik Schick is currently one of the best centre-forwards in the world. Renewing with him is a real sign of intent on our part," commented outgoing Leverkusen CEO Rudi Völler, who will officially step down on 1 July 2022.
"He knows that he has great teammates with us who can play balls from all positions and who can develop his strengths to the max. I'm looking forward to seeing him in a Leverkusen shirt for years to come."
Schick has won 33 caps for Czech Republic, scoring 17 goals.
He was joint top scorer at last summer's European Championship with five goals, including the goal of the tournament with an outrageous strike from the halfway line against Scotland in the group stages.
