Ethan Lewis was pulled out of class and made to take all his lessons under the supervision of his form tutor after he went back to school after summer with the extreme, Native American-style cut.
His mother, Romaine Coonghe, criticised Strood Academy in Rochester for not being sensitive to Ethan's ethnicity - even though they allowed him to have the same style last year.
She said: "We live in Medway, and it's not the most diverse place.
"There aren't many kids with afros around here.
"I feel this is discriminatory as Ethan has partly Afro-Caribbean style hair and partially European hair.
"The school doesn't seem to understand how difficult it is to keep his hair neat so we try to keep it as short and tight as possible."
When he arrived at school last week, Ethan was told that he had flouted uniform rules.
According to his mother, he won't be allowed back into lessons with his classmates "for the foreseeable future".
She said: "The headmistress told me that they wanted to make an example out of Ethan, to show other kids what not to do.
"I did not think that was very appropriate at all.
"It is absolutely outrageous, especially when a child has learning difficulties.
"He's a very timid and shy boy, so it was humiliating for this to happen to him."
Ethan has sensory problems, meaning he gets distressed when he goes to have his hair cut, so his dad Russell Lewis cut his hair at home.
Romaine said: "It is so unfair that he has been humiliated and made an example of. It is almost like he is being treated as a criminal - it is too severe.
"He didn't even want a haircut, and it was our mistake for cutting it too short.
"I understand that rules are rules but what difference does 0.5 centimetres of hair make?"
Ethan occasionally does child modelling, and his signature Mohican has helped him get jobs in the past.
Romaine added: "He's had this haircut since he was seven and it was never a problem in primary school, though he was pulled up on it once in January.
"People know him for his Mohican."
Responding to Ethan's mother's accusations, Strood Academy's principal Kim Gunn defended her decision to pull Ethan out of class.
She said: "For us it's about standards. At the end of the school year we sent out a letter to parents and then again during the holidays.
"We detailed exactly what the pupils should be wearing, including uniform, jewellery and hair. We have said no extreme haircuts and the head teacher has the final say.
"I can understand there may be extenuating circumstances but it is a basic ground rule - if pupils think they can get away with haircuts then they will think the teachers won't mind if they start misbehaving.
"If other pupils see their peers with different haircuts, they will want one too, so all pupils breaking the rules have been removed from their classes.
"They are not missing any learning, they are working with their form tutors."