On transfer deadline day, Liddle has signed a long-term deal at the Proact Stadium after City and Chesterfield agreed an undisclosed fee for the 29 year-old.
The deal is subject to the relevant clearances from the Football League and The Football Association.
Liddle has played 26 times for Phil Parkinson's men this season, scoring three times.
After joining the Bantams in back in June 2014, Liddle made 76 appearances in total for Parkinson's side.
The Club would like to place on record its thanks to Gary for all of his efforts in a Bradford City shirt and wish him all the very best at Chesterfield.