Amari Allen says the assault happened during break time at her private school in Springfield, Virginia, on Monday.
She alleges that the boys held her down on a slide and called her hair “ugly” and “nappy” and cut some off.
The alleged attack took place at the Immanuel Christian School, where the US Vice-President’s wife teaches.
“The boys came up to me and they ambushed me sort of, like caged me in,” Ms Allen told local media.
“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.”
The family say the incident only came to light on Wednesday when her grandmother noticed her hair was suddenly different lengths.
“It’s very painful,” Cynthia Allen said. “I want to see them dismissed from the school. I want to see something done.”
In a statement, the school said they had asked local police to investigate 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,” Immanuel Christian School said in a statement.
“We are deeply disturbed by the allegations being made, and are in communication with the family of the alleged victim to gather information and provide whatever support we can.”
She resumed working at the school earlier this year, amid scrutiny over its anti-LGBT requirements of staff.