The 21-year-old midfielder, who had reportedly attracted the interest of a number of Football League clubs, spent three months on loan with the Dons last season.
"We were very sorry to lose George when he went back to Norwich because he was probably the highlight for us in a struggling team at the time," AFC Wimbledon boss Neal Ardley told the club's official website.
"I really enjoyed working with him then because you could see the quality he had. As soon as I knew the player would be leaving Norwich I threw my hat into the ring.
"I spoke to his agent in early May because I knew I would have to do a bit of work to get him. I had to try and put the budget in place so that we could make an offer that could bring George back here I am delighted that George has joined and he is a great signing for the club."
AFC Wimbledon narrowly avoided relegation from the Football League last season.