Kevin Pressman has left his role as goalkeeping coach at Bradford to take up the same position with Championship club Millwall.
The 44-year-old ex-Sheffield Wednesday keeper joined the Bantams' coaching team in August 2011.
Pressman wrote on his Twitter account: "Wishing everyone at Bradford City Fc all the best for the new season. Looking forward to a new challenge at Millwall FC."
Bantams manager Phil Parkinson told the club's website: "It is a shame to see Kev leave the football club but he goes with our best wishes.
"We wish him all the best in his new career move and we now focus on naming his replacement in plenty of time for the new season."