The Italy midfielder has penned terms to 2029 with the Serie A title winners.
“Today I am extremely happy and moved to extend my contract with Inter for a number of years,” Barella told the official Inter website.
“I have never had any doubts: I believe in this project and, most of all, I wanted to sign before the European tournament. I am truly proud to be able to keep fighting for the colours of this great Club for years to come.
“My wish is to continue on the successful journey that the squad and coach have experienced in recent years. We want to keep growing and bring more joy to our fans. We have had unforgettable moments with them and I am sure there will be many more.
“I cannot wait to go again in front of the wonderful Nerazzurri fans, all of us together for Inter.”