In a statement on its website, the FA said: "Kevin Keegan has been charged with a breach of FA Rule E3 for abusive and/or insulting words and/or behaviour to referee Steve Dunn following the match at Newcastle United on Sunday 24 October.
"He has until 09 November to admit or deny the charge.
"The charge does not relate to Keegan's post-match media comments, which will not be subject to disciplinary action."
Keegan's post-match comments, which made his feelings quite clear to the media, included: "The word, 'homer', comes to mind for the referee - every decision went their way.
"The little insignificant decisions went our way but they got the major ones. I am very disappointed with his performance. You need a strong referee at a place like this and we didn't have one."