Kelly Carney, 39, from Wallasey, Merseyside, said her 15-year-old daughter Faye Carney was banned from lessons and put in internal exclusion on Tuesday 6 September over the £60 dye.
The highlights, put in three weeks ago ahead of a family wedding, marked the first time Faye, a Year 11 pupil at St Mary’s Catholic College, had been allowed to have her hair dyed.
“Faye’s highlights are so natural they are almost invisible – her hair just looks the same as before,” Carney said.
“But there is nothing extreme at all about this at all, it is so subtle.”
Carney said Faye was “hauled out of her tutor group” by a teacher at 8.30am on her first day back and spent the whole day in the school’s internal exclusion zone.
She said Faye was told if her hair was not dyed back she would be permanently excluded or taken to the school’s sixth form salon to have her locks altered there.
Carney said the school had previously sent a letter home to parents about changes to rules regarding uniform, makeup and hair.
The letter stated children could not have “extreme” hair colours, cuts or styles.
“It’s not pink or green or orange, it’s not even bright blonde,” Carney said.
“It was the first time Faye has ever been allowed to have highlights. She has always been a good student and this is just ridiculous.
“The school should be concentrating on the kids’ education, not what they’re wearing.
“The kids are suffering big time because of this.
“Faye is in Year 11 now and this is the most important year of her education, but she spent her first day in internal exclusion without any breaks.
“Parents have already had to buy new uniform because of the school’s change to academy status and we have not been reimbursed for this, despite the school being based in quite an underprivileged area.”
The St Mary’s uniform and appearance policy, sent to all parents, states: “Students are expected to wear hair in a neat and acceptable style.
“Hair must be of one colour, natural in appearance.
“Hairstyles (including shaved heads) judged to be extreme by the headteacher are not permitted.”
On Wednesday 7 September, Carney said she sent her daughter to school with her hair up and with a note asking teachers to contact her if they took exception to the dye, but she has not yet heard back from teachers.
The school has been contacted for comment by The Huffington Post UK.