Allardyce said in a statement, "After nearly eight privileged years with Bolton Wanderers Football Club, I would like to announce that, after careful consideration and dialogue with my close family and senior officials within the football club, I will be resigning as manager of the club with immediate effect."
"It was mutually decided that I step down now rather than at the end of the season, to give my successor the ideal opportunity to experience the preparation and build up of matchday in readiness of next season.
"The decision to leave the football club, which has been my spiritual home for over 18 years, as both player and manager, is one of the hardest decisions I have had to make in my life.
"However, after guiding the team into a position where the club is on the verge of qualification for European football for the second time in three years, which has been the accumulation of almost seven years of strategic building and hard work across all areas of the football club, I feel it is the right moment to step down from my duties and welcome a new exciting era for the club under different leadership.
"I feel the club is in a great position to continue its upward trajectory with a talented internationally recognised squad, supported by an excellent Academy programme across all ages working under the guidance of a highly-skilled football management team.
"I believe the foundation of the next phase for the next development stage of the club is well and truly in place. It is with this knowledge that I feel confident that I am moving on with my life content with a legacy that I have tried to create for this special club and I wish the owner, chairman, staff, players and above all the fans every success in the future."
The 52-year-old took charge at Bolton in 1999 and transformed their fortunes, turning The Trotters into a solid Premiership outfit.
Good Luck Sam, we are very thankful.