Sanders, 19, signed from Charnock Richard earlier in the season and has been an ever present since November.
Chairman, Jon Eeles, said: "We are a lucky to have a good set of lads at the Club presently, and Jack has been a great addition to that.
“We are playing good football at the moment with the defence looking particularly solid and have lowest goals conceded in the Division.
“Jack is proud to play for Leek and that comes over when you talk to him, we are all very pleased he has committed his future to the Club."
Centre-back Sanders played against Leek for Charnock Richard in the FA Cup earlier this season, catching the eye of Blues boss Neil Baker.