Meredith's previous contract with City ran out at the end of the current campaign but his improved deal with now come into place for the remainder of this season and the next two after that.
The Australian has played 43 times for the Bantams this season, making the left back slot his own once again in City chief Phil Parkinson's starting eleven.
Meredith, who turns 27 this Sunday, has featured 116 times in total for Parkinson's men after joining Bradford from York City in the summer of 2012.
He said: "I'm delighted to sign this deal. It is fantastic news for me.
"I am pleased to get this deal signed before the summer break so I can concentrate on our final games of the season.
"It is a good club to be at and I want to achieve more success here.
"The memories from our cup runs and our promotion from League 2 are ones that will stay with us all forever.
"The plan now from the Gaffer is to keep making more good memories and more good times here at Bradford.
"There is a great culture at this club. It is a culture of working hard and everyone pulling in the right direction.
"We are continually pushed to be the best we can be. We are prepared well for matches and training, and the coaching and backroom staff really look after us.
"The stadium is great, the staff are fantastic and the support we get here from the fans is truly superb.
"After being here three seasons, I want to continue being here for the long-term."