Moyes, who has been linked with the Scotland job if Gordon Strachan was to leave, was charged by the FA following a conversation which took place between the Scot and BBC Newcastle and Radio Five Live reporter Vicki Sparks at the end of a post-match interview.
Moyes was unhappy with one of Sparks’ questions and said to her: “You were just getting a wee bit naughty at the end there, so just watch yourself. You still might get a slap even though you’re a woman. Careful the next time you come in.”
The Football Association on Friday said he was guilty of “improper and/or threatening remarks” following the match against Burnley.
Although the interview was over at the time Moyes made his remark, the camera was still running and footage of the incident was published three weeks later by a national newspaper.
Moyes was contrite about the incident when questioned at a subsequent press conference.
He said: “In the heat of the moment, I made a mistake in my comments to a BBC reporter, which I profoundly regret. I was disappointed with myself for it.
“I subsequently phoned the reporter and apologised, which she accepted. It’s not my character, it’s not my type, as most people know and once again I apologise for it.”
The club described Moyes’ conduct as ‘’wholly unacceptable’’ but stood by him as he attempted - in vain - to preserve Sunderland’s Premier League status.
Moyes denied the charge but the FA’s independent regulatory commission upheld it.
An FA statement read: “David Moyes has been fined £30,000 in relation to comments he made after the Sunderland versus Burnley game on March 18, 2017.
“It was alleged his remarks were improper and/or threatening and/or brought the game into disrepute, contrary to FA rule E3(1).
“He denied the charge, however it was found proven following an independent regulatory commission hearing.”
Moyes resigned from his role at the Stadium of Light on May 22 following Sunderland’s relegation.