Law Lords are to rule on the case of a Muslim girl excluded from school for wearing a traditional jilbab gown.
Shabina Begum was told her jilbab was a health and safety hazard
Denbigh High School, in Luton, Beds, is challenging last year's Court of Appeal ruling that it acted unlawfully.
The court ruled it infringed the human rights of Shabina Begum by not giving due consideration to her beliefs.
The Law Lords will also consider the case of Abdul Ali, excluded from Lord Grey School in Milton Keynes, Bucks, over a fire in a waste bin.
Both students are represented before the Law Lords by human rights lawyers Cherie Booth QC and Carolyn Hamilton.
They are backed by the Children's Legal Centre, which said the cases were the first of their kind to reach the highest court since the introduction of the Human Rights Act 1998.
Shabina, now 17, began wearing full-length Muslim religious dress to school in September 2002, when she was 14. She was told it did not comply with the school's uniform policy and was a health and safety hazard.
She was out of school for almost two years before attending another, wearing the full-length jilbab.
The appeal court said the school had failed to give due consideration to Shabina's religious beliefs in reaching its decision.
The Lords will consider whether the school violated Shabina's right to education and her right to religious freedom.
When she won her appeal court case, she said the school's attitude was part of an atmosphere created in Western societies since the 11 September attacks on the US in 2001, "in which Islam has been made a target for vilification in the name of the 'war on terror'".
On Wednesday, Shabina told BBC Radio 4's Today programme wearing the jilbab in public was an "obligation" and banning it had meant she "was not able to practise my religion at that school".
"My human rights were being infringed," she added.
"I was willing to wear the colours of the school.
"I was willing to wear the logo and the jumper - on top of my jilbab."
Her barrister, Carolyn Hamilton, told Today: "Shabina and other Muslim women, or any other woman or child, should not be denied their right to education for religious reasons."
Shabina had "very strong views about her religion... and following it according to her beliefs", Ms Hamilton added.
Excluding her had been "clearly unacceptable", she told the programme.
If the Law Lords ruled in her favour, schools would also have to allow Muslim girls to wear headscarves, Ms Hamilton added.
In the Abdul Ali case, the Court of Appeal ruled previously that his human rights had been violated - a judgement being challenged by Abdul's former school.
Abdul's exclusion happened in 2001 when he was 13, after he and two other boys were accused of causing smoke damage.
Police investigated the incident and did not proceed with charges, but Abdul remained out of school for 10 months, receiving no education.
Edward Faulks QC, for Lord Grey School, told appeal court judges that when police finally announced there would be no prosecution, neither Abdul or his parents attended a meeting to discuss his reinstatement.
Mr Faulks said the school permanently excluded him after he failed to return. Only then did the parents decide they wanted him to return.
The Lords will decide if his exclusion amounted to a breach of his human rights.
Julia Thomas, an education lawyer at the Children's Legal Centre and solicitor for Abdul, said: "We trust that the House of Lords will uphold the decisions of the Court of Appeal which ruled that the schools acted in violation of the Human Rights Act by denying both children their fundamental right to education."