Collins lasted just 6 games.
Bradford City have sacked head coach Michael Collins.
Collins, who was the youngest boss in English football, was promoted from his role as the clubs under-18's manager back in June.
Bradford have lost four of their past five league matches and were knocked out of the Carabao Cup on penalties by Macclesfield last month.
Chairman Edin Rahic said: “Stefan (Rupp) and I would like to take this opportunity to thank Michael for the work he has done for the club.
“The decision is based on an unsatisfactory start to the season and performances not being good enough. We anticipated a much better start and the results have not matched expectations.
“We have acted swiftly to appoint a new head coach who we believe will take us towards achieving our goals this season and beyond.
“We care massively about this football club and believe this decision has been made at the right time, with everything very much to play for.
“We are now looking forward to naming our new head coach and moving forward, together, in a positive manner.”
City’s new head coach will be unveiled at some point today.