He said: "Last term they started saying my hair was too long and that I needed to get it cut to have it clear of my collar.
"We agreed that I would tie it back but then we received a letter saying that if my brother and I didn't get our hair cut we would be punished.
"I don't think they have the right to say that and I'm not going to get it cut no matter what they say.
"My plans are to go on to do A-levels but I don't think I'll do that in the sixth form at St Margaret's.
"I was punched in the eye at school in 2003. I had a couple of operations and have had pain and vision loss ever since but now I'm being punished because of my hair."
The boys' mother, who asked not to be named and also has an 11-year-old daughter and an 18-year-old son, is backing their decision to keep their hair long.
She said: "I have investigated this issue and the government directive states that pupils should not discriminate on the grounds of gender and if my daughter can have her hair tied back at her school, why can't my sons."
The father of a 15-year-old from Childwall excluded for five days for refusing to cut his hair said: "I presented my son today to the deputy head with his hair tied back and in the correct uniform but they have still said he must be excluded.
"I am unhappy about the way this has been carried out and the fact that my son was sent home with a letter rather than speaking to me directly."
Yesterday the school declined to confirm how many children were excluded but said it was a "small number".
Dr David Dennison, headteacher at the school, said: "St Margaret's has an excellent city-wide reputation for the high expectations in respect of personal and academic standards.
"Parents are aware of these expectations on application and are regularly reminded of them by newsletter."