The 35-year-old, who has made 10 appearances and scored once since rejoining the club in the summer, has now joined Bradford.
"Andy is an excellent professional and we wish him well at Bradford," Leeds boss Neil Warnock told the club website.
Gray also had a spell with the Bantams earlier in his career, playing 81 games and scoring 21 goals between 2002 and 2004.
Gray said: "I wish Leeds every success and hope the club win promotion back to the Premier League."
- Sports & Recreation