The alleged incident took place earlier this week at the Immanuel Christian School in Springfield, Virginia, where US Vice-President Mike Pence's wife teaches, according to media reports.
The girl, Amari Allen, said the assault happened during break time at her school on Monday. She alleged that the boys held her down on a slide and called her hair "ugly" and "nappy" and cut some off.
The family said the incident only came to light on Wednesday when the girl's grandmother noticed her hair was suddenly different lengths, according to the BBC.
"The boys came up to me and they ambushed me sort of, like caged me in. And so they put their hands over my mouth. They put my hands behind my back and they started cutting my hair and told me that I was ugly," Allen told the local media.
"They like took my lunch and ate it in front of me and told me I didn't deserve it, that I could just starve and stuff like that."
The school and local police said they were investigating the incident.
"We take seriously the emotional and physical well-being of all our students and have a zero-tolerance policy for any kind of bullying or abuse," the school said in a statement.
( With inputs from IANS )