A principal of a high school in the US state of South Carolina is facing backlash after she allegedly told teenage girls that wearing leggings made them look “fat”.

During a school assembly held on Tuesday to speak to students at Stratford High School about ‘appropriate attire’ for school, Principal Heather Taylor old a group of Year 10 girls that leggings “show everything” when worn as pants.

“[Leggings are] not meant to be your actual pants, and if you have a shirt that comes to here, then you are showing everything. Yes, everything,” Taylor can be heard saying in a recording of the assembly provided to WCBD News.

"The sad thing is with that, ladies - if someone has not told you this before, I'm going to tell you this now — unless you are a size zero or a two...even though you are not fat, you look fat," she continued.

Concerned parents flooded the school's Facebook page upon hearing what the principal had told the students, in a slew of since-deleted comments.

"You are responsible for all of the kids that go to your school," one user wrote.

"Due to your poor choice of words you may have instilled a lot of horrible things in the student community."

Others called the principal's body-shaming stance "appalling" and said she owed the entire student body an apology.

"I'm disappointed but not surprised," one woman wrote, while another added, "You are supposed to set a good example for all the students. You failed."

Allison Veazey was present at the assembly and said she felt "targeted" by her principal's words.

“I’m not a size zero and I kind of felt targeted because of my size,” she said.

Do you think it's appropriate for a principal to make these sort of remarks?