For several years, the protests were large against Manchester United's former owner, the Glazer family.
Last year, Sir Jim Ratcliffe took over – but the results have not convinced and the loud opposition remains.
The club is in 14th place in the Premier League and was eliminated from the FA Cup a few days ago after a penalty drama against Fulham.
And now, the supporters' association "The 1958's" has made a statement asking people to wear black in Sunday's home game against Arsenal.
"The club is slowly dying before our eyes, on and off the pitch", they write, and then continue.
"The club is going backwards and it will likely get even worse."
Similar actions have taken place in United's history. In 2005, supporters were asked to wear black in the FA Cup final, also against Arsenal. That protest was in connection with the change of ownership to the Glazer family.
