The England defender entered the final year of his contract over the summer, but has now signed an extended deal which will keep him at the Etihad Stadium until 2026.
“I’m thrilled to sign a new deal. My future is with Manchester City and that is the best thing for me,” said Walker. “I’ve enjoyed every single moment of the past six years at this fantastic Club. I have an amazing coach, great team-mates and staff and our fans are the best. I feel supported on every single level.
“The Treble-winning season is one I will never forget and we’re ready to go again and try to win more trophies. I am delighted to continue at a club that competes for trophies every year and I can’t wait to see what the next few years bring.”