The Poland international has established himself as the Turin giant's first-choice keeper since Gianluigi Buffon joined Paris Saint Germain ahead of the 2018-2019 season.
Juve announced that Szczesny, signed from Arsenal in July 2017 after spending two seasons on loan at Roma, has extended his stay with the Serie A title contender.
The 29 year-old has made 84 appearances for the defending champions\, winning the Scudetto twice, and the Coppa Italia and Supercoppa Italiana once apiece.
Szczesny has been commanding for Maurizio Sarri's side this season, keeping Buffon on the bench for much of the campaign after the Italy icon's return to the club.
"This is a demonstration on behalf of the club of the trust they have in me, and so I am very happy," Szczesny said. "I will look to keep giving my best in the next few years with Juve.
"I am here until 2024 and I want to win everything. This is the objective of the club and the players. We need to sweat, to run and sacrifice to achieve the objectives, which is more trophies and titles."
After 23 Serie A matches this season, Juve is second to Antonio Conte's Inter, trailing on goal difference.