The Swede will remain at San Siro if the Rossoneri can climb into the top four by the end of May
Zlatan Ibrahimovic has a clause in his AC Milan contract that will see him automatically renew his deal with the club for the 2020-21 season if Champions League qualification is secured.
The Swede arrived for a second spell at the San Siro club in January after a spell playing in MLS with the LA Galaxy and has returned three goals and an assist from nine appearances.
The fortunes of the club have improved notably since his return, with the only defeat they have suffered coming against Inter in the derby, a match in which they held a 2-0 advantage.