MTV has sicced its lawyers on the author of a dishy new tell-all about its hit series “Teen Mom,” Page Six has learned.

We’re told that after a chapter of the book “You Have No F**king Idea” — written by Matt Baier, the fiancé of one of the show’s longest-standing stars, Amber Portwood — leaked, Viacom ­attorneys pounced and demanded that its publisher slash around 15,000 words.

Sources say that most of the offending copy — which accounted for some 20 percent of the original manuscript — was about the network itself and Portwood’s nemesis,

fellow cast member and sometime porn star Farrah Abraham.

Baier — who also appears on the show, which debuted in 2009 — had agreed to let MTV review the book before publication. But when the leaked chapter began circulating online before the network had seen it, we’re told that network execs “got in a tizzy and read [Baier] the riot act” — then had a senior attorney take a red pen to the text, which is due to be published by Post Hill Press in May.

Among other allegations, Baier claims in the leaked chapter that an MTV producer told Portwood and Baier to “do their research” on Abraham’s boyfriend, after which

Baier claims that the boyfriend had “got into a lot of trouble for ­assaulting his ex-girlfriend.”

He also claims that Abraham’s family tried to control stories about themselves in the press “by way of threats and intimidation.”

Baier also claims that a former producer on “Teen Mom” told him that Abraham’s father had a “history of physically assaulting people,” and that Portwood had told the network that she “wasn’t comfortable being the same room as Farrah” before a “reunion show” taping at which they ended up in a physical confrontation.

And before the fight, “security — who had followed us around all day long — suddenly was nowhere to be found. Not to get into any conspiracy theories, but it was almost as if they wanted there to be an altercation.” A rep for Abraham denied Baier’s claims about her family and her boyfriend. Reps for MTV, Baier and Post Hill Press didn’t get back to us.