The lock captained Tigers for the first time in their season opener at Exeter in August, but has featured only four times to date this term because of an injury suffered while training with the national side.
Since making his senior debut for Tigers in 2020, he has made 60 appearances for the club.
Leicester head coach Michael Cheika said it was “really important for the club” that Chessum committed his future to the East Midlands side.
“Ollie is 24, home grown, has Leicester Tigers in his blood and is a high-quality player,” Cheika said.
“He has been introduced to a leadership role within the team earlier this season and showed good skills given the opportunity. I’m very happy he will be part of the club these coming seasons.”