A club statement on Monday evening confirmed that his tenure had been brought to an end “with immediate effect” along with assistant Tony Docherty, with the pair leaving their posts by mutual consent.
Under 20 coach Paul Sheerin will take charge of the first team on an interim basis for the remaining six league matches supported by Barry Robson and Neil Simpson as the Dons look to secure a third placed finish.
The move follows a poor run of form that has resulted in only one win in nine matches, with only one goal scored during that run, which included setting an 118-year-old club record of failing to find the net in consecutive games.
Club owner Dave Cormack said: “During his time in charge Derek raised the bar and delivered a level of consistency not seen at the club for many years, qualifying for Europe each season, and delivering a memorable Scottish League Cup win at Celtic Park in season 2013/14 with 43,000 Dons fans in attendance.
“Clearly, results since the turn of the year have been disappointing and frustrating for everyone. Derek and I reviewed where we were and agreed that this was the right time for him to step down. The club now has the opportunity to appoint a new manager ahead of the new season where, with a number of players out of contract, we have work to do to build a competitive squad.
“Derek and Tony leave with our thanks and gratitude for what they have achieved during their tenure. We wish them well for the future.”
Cormack added: “The board will start the search for the new management team immediately and has a clear timetable in place. In the meantime, we believe we have a robust interim solution for the rest of the season and the Scottish Cup which is still all to play for.”
McInnes took charge of Aberdeen in March 2013 and guided the club to its first silverware in nearly 20 years with the League Cup victory in 2014 before delivering four consecutive runners-up finishes between 2015 and 2018.
However, the Dons have slipped to fourth in recent seasons, and are on course to do so again as they currently lie three points behind third-placed Hibs, who have a game in hand.
Commenting on the his departure, McInnes said: “This season has been unprecedented due to a number of factors and I am as frustrated as anyone that results haven’t been of the high standard which we set.
“My motivation to deliver success has never wavered and during my eight-year tenure my staff and I have worked hard to elevate expectations and set a minimum standard which should be demanded at a club like Aberdeen FC.
“I would like to thank all the players who have featured in my teams over the years, my current staff and players for their efforts and all the staff behind the scenes for their hard work and endeavour. To the supporters for their continuous backing and, of course, the board for their support during my time at the club.”
Supporters appeared to have turned against McInnes this season, venting their frustration over results as well as the brand of football on display from the Dons.
McInnes had spoken of his own frustration at the way the club handled the January transfer window, which saw three strikers depart the club on deadline day on the back of a spate of injuries.
The former Rangers midfielder turned down the chance to return to Ibrox in 2017, and also rejected an approach from Sunderland in order to remain at Pittodrie.
In the face of criticism this season, the 49-year-old had vowed to battle on in the quest to secure European football, something he achieved in every full season in charge, but the club will now look for new boss.