Investigators said the 12 and 13-year-old culprits set up the page posing as another girl, 12, whose parents reported it to the Hood County Sheriff in June, according to CBS DFW.
Investigators arrested the girls Monday on a third-degree felony charge of online impersonation.
They said their daughter was threatened at school by another student because of remarks on the bogus social media page. In reality, the bullied victim was not allowed to use Facebook, and didn't have her own page, CBS DFW reported.
The parents say the site was headlined with a crass nickname for their daughter, alongside a picture of a child actress they said she resembles.
"A whole bunch of vulgar things, just on the introductory page," said the girl's mother, who asked not to have her name revealed. "Not including all the things that were posted threatening fellow classmates."
Sheriff Roger Deeds said investigators did not know at first that girls were responsible. He said the girls didn't back off after being found out.
He called it bullying and similar to identity theft.
"Instead of using it for financial gain, they're using it to hurt people," the sheriff said.
The middle school suspects were taken to the Granbury Regional Juvenile Detention Center.
Visitors to the page can still access it, but now see a Hood County Sheriff shield, and a message that reads, "This fictitious Facebook page has been seized by the Hood County Sheriff's Office."
The Granbury Independent School District was not involved in the investigation.