On the Wanderers board since 1988, he served as club chairman from 1999 until stepping away from his duties in November due to illness.
Bolton said in a statement on their website: "Bolton Wanderers Football Club is deeply saddened to announce that long-standing club chairman Phil Gartside has died aged 63.
"Phil has passed away after a short and brave battle with cancer."
Bolton vice-chairman Brett Warburton said: "Phil has been a personal friend for over 30 years and this is a very sad day for everybody associated with Bolton Wanderers.
"On behalf of Eddie Davies, the board and everyone associated with the club we send our deepest condolences to all Phil's family and ask that their privacy is respected during what is a difficult time for all involved."
Bolton said in their statement that Gartside's funeral will be a private service, in line with his family's wishes.
A number of Wanderers players past and present took to social media after the announcement to pay their respects.
Bolton midfielder Josh Vela tweeted: "Rip Phil gartside thoughts and prayers go out to his family #bwfc".
Team-mate Neil Danns posted a similar message - "Rip Phil gartside prayers go out to his family" - as did Craig Davies.
"Sad to hear about Phil Gartside was always a top bloke with me," the forward said
"My thoughts are with his family".
Source : PA
Source: PA