Roberto Martinez has been fined £10,000 following comments made after Wigan's game with Manchester United last month.
The Wigan boss admitted a charge of misconduct in relation to remarks made about Danny Welbeck following the Latics' 4-0 defeat at Old Trafford.
Martinez was unhappy about a controversial penalty awarded to United as well as a challenge by Welbeck on Franco di Santo, which the Spanish boss believed should have warranted a red card.
A statement on the FA website read: "The charge was in relation to a breach of FA Rule E3 concerning media comments which implied that the match referee and/or match officials in general are motivated by bias and/or brought the game into disrepute.
"Martinez, who had requested a personal hearing, was also warned as to his future conduct."
Following the game, Martinez said: "I have come to United three times before today and for whatever reason we don't seem to be measured in the same manner as the team at home.
"Today the penalty is as bad a decision as you are going to see in the Premier League. In many ways, you feel as though you are fighting against a mountain.
"There were tackles flying around that if they had been the other way round there would have been a couple of red cards."