The Northern Ireland international's extended terms are due to expire at the end of the 2016-17 season.
McArdle, 27, joined Bradford from Aberdeen in June 2012.
"Having spoken to the manager already this summer I'm excited about the future for the club and I want to be a part of it," he told the club's official website.
"The progress the club has made in the two years that I've been here already has been very impressive. To me, it shows the club is moving in the right direction."
McArdle made 45 appearances for the Bantams last season.