UFC's Mark Munoz Placed On Admin Leave From H.S. Job After Letting Kids Box Each Other

Mark Munoz -- a former UFC fighter who beat Demian Maia in 2011 -- has been placed on administrative leave from his high school wrestling coach job ... after he let quarreling students box each other, TMZ Sports has learned.

Munoz accepted a job to be the H.S. wrestling coach at Fairmont Private Schools in Anaheim, Calif. back in Sept. 2020 -- but we're told things at the gig went awry just recently.

According to sources close to Munoz, two students got into an argument on the playground ... and then went to Munoz -- who we're told was not made aware of the tiff -- to ask if they could put on boxing gloves and settle things.

The 44-year-old, per our sources, allowed the scrap to happen -- but we're told the ex-UFC fighter believed the impromptu boxing match was more jovial than violent.

We're told, however, one of the boys' parents was outraged about the scrap -- and went to administration over it all.

A school spokesperson declined to get into the specifics of the allegations against Munoz, but did confirm the coach has been placed on administrative leave through the end of this school year and will not have his contract picked up once it ends.

"[He] will not be returning to campus," the spokesperson said.

The school had previously been thrilled to add Munoz to its staff -- saying in a statement following his hiring that he has a resume that "reads like a 'Who's Who' in the sport."