Kay has put pen to paper on a deal to keep him in Milton Keynes for the Dons’ maiden Championship campaign, extending his stay with the club into a fourth season.
The 32-year-old said: “I’m very happy to sign. This season coming will be my fourth here, which is the second-longest spell I’ve ever had with a club – I’m really enjoying my time here.
“The chairman and the gaffer knew that I wanted to stop here and thankfully they wanted to keep me too, so it was good for both parties.
“Last season was very special, getting promoted in the way that we did, and I’m excited to get started again. I enjoyed the celebrations but the hard work starts now – I’ll be ready and raring to go when we’re back in for pre-season.”
Kay played an important role in the Dons’ promotion-winning campaign, featuring in all-but one of their 46 league fixtures.