Inzaghi replaced Antonio Conte as Inter manager in the summer of 2021 and has won two Coppa Italia trophies and the Italian Super Cup twice during his time in charge of the club.
Last season, Inzaghi led Inter to their first Champions League final in 13 years but suffered a 1-0 defeat to Manchester City.
Inter Milan have started the 2023/2024 season with three straight wins heading into the international break.
"Inter Milan are delighted to announce the extension of the contract of their coach Simon Inzaghi, who is now tied to the club until 2025," said the Lombardy club's brief statement.
Inzaghi will hope to mark his new contract with a priceless victory against city rivals AC Milan right after the international break.
