The loyal manager has left Champion Hill following the club’s slow start to the new season.
Dulwich sit in the National League South bottom four and have lost their last four matches.
Appointed in 2009, Rose leaves south east London Hamlet as the club’s long-serving manager ever.
Ben Clasper, the club’s chairman, released an emotional statement telling fans the difficult news.
The club face fellow early season strugglers Hemel Hempstead on Tuesday night.
The announcement read: “It is with enormous personal sadness that I have to announce that the club has decided not to complete and execute the contract extension for Gavin Rose’s role as men’s first team manager and he will leave the position with immediate effect.
“It has been an honour and a pleasure to work alongside Gavin over the past four years and whilst we all knew the reality was that all managers eventually move on it was genuinely difficult to accept that time would ever come for us.
“Simply thanking Gavin for all that he has achieved and wishing him every success in future feels hopelessly inadequate, he will always be part of the Dulwich Hamlet family and I sincerely hope this will not be the end of our association either personally or professionally.
“Gavin has been responsible for many of the all-time high moments in living memory at the club and his contribution deserves the legendary status I have no doubt it will gain as people look back on what he has achieved here since his appointment in 2009 which makes him the club’s longest serving manager.
“It is both those moments and the length of service that have been at the forefront of everyone’s minds as the board have worked hard on making the tough decisions in many areas both on and off the pitch to the benefit of Dulwich Hamlet Football Club and which we believe are necessary to deliver the long-term objectives we set in October 2018 when supporters stepped in to save and then rebuild the club.
“The departure of any manager from any club is a difficult decision as it impacts everyone associated with the club but I say with no hint of exaggeration that I believe few clubs have been through a change of this magnitude and everyone at the club understands how de-stabilising this will be and is committed to steering us through the times ahead and the challenges that are bound to arise.”