Ariana Iacono, 14, has been suspended from Clayton High since last month.
Iacono and her mother belong to a religious group called the Church of Body Modification. The school says her nose stud violates the dress code, but the ACLU believes the Iaconos’ rights are being violated by the policy.
"I realize everyone thinks she can take the nose stud out and go, but in America, we do not make people sacrifice religion to get an education," ACLU attorney Jon Sasser said.
Johnston County school officials denied Iacono's appeal of her suspension on Tuesday. The decision means she won't be allowed to return to Clayton High for the remainder of the school year.
Instead, she will be sent to South Campus Community High School, according to the lawsuit.
Iacono was suspended four different times this school year for wearing the nose stud at school.
"The dress code policy allows for a religious exemption, and I explained to the principal and various school officials how my daughter’s nose stud is essential to the expression of our family’s religious values," the teen's mother, Nikki Iacono, said in a statement. "Ariana had gotten excellent grades in middle school, but now she is in danger of flunking out of her freshman year of high school because the principal won't let her back in class unless she removes her nose stud or covers it up, which is asking her to hide her religion."
The Church of Body Modification has 3,500 members in the U.S., according to the lawsuit. It was incorporated in Pennsylvania in July 2008.
Iacono pierced her nose in August to join the church.
The lawsuit seeks a court order allowing Iacono to return to Clayton High immediately, to be allowed to make up the work she has missed, and to suffer no further consequences for having the piercing.