Faryal Bhatti was accused of blasphemy by officials at Sir Syed Girls High School in Pakistan Ordnance Factories (POF) colony in Havelian, near Abbottabad.
The accusation was made after she misspelled a word in a class test on a poem praising the Prophet Muhammad.
She was reportedly beaten by her teacher over the mistake before the school took the decision to expel her.
A rally was held by local Muslims demanding that criminal charges be brought against Bhatti. At Friday prayers last week, imams said her entire family should be punished.
The decision to expel her was taken by officials following a meeting with the girl and her mother in which Bhatti apologised and tried to explain that it had been a simple spelling mistake.
The girl's mother, a nurse, has since been moved by the authorities from her place of work at a nearby hospital to another hospital further away from the school.
Wilson Chowdhry, head of the British Pakistani Christian Association, said this was not an isolated incident and that Christians in Pakistani schools are forced to take Islamic lessons and face pressure to convert or take part in Islamic worship.
He said Bhatti's expulsion "demonstrates that too often there is little difference between the 'mainstream' and 'extremist' educational establishments in Pakistan".
He criticised the British Government's decision to continue investing millions of pounds in Pakistan's education system when it "routinely and systematically discriminates against and oppresses children of minority religions, and effectively increases Islamic extremist practices".
"Without extremely stringent controls and monitoring, it is highly likely that even without any of the regular brand of corruption, Cameron will have pledged hundreds of millions of tax-payers money to an education system that effectively furthers Islamic extremism and imperialism at the expense of minority faith children," he said.
The Centre for Legal Aid, Assistance and Settlement, which provides free legal support to persecuted Christians in Pakistan, has also condemned the blasphemy claims against Bhatti.
Its UK coordinator Nasir Saeed said: "The spelling mistake that Bhatti made was a matter of adding one dot to a word. Just a single dot has made her a criminal and changed her life.
"It is a mistake she may have to pay for the rest of her life as blasphemy charges carry a terrible stigma .
"This is yet another demonstration of how wildly Pakistan's blasphemy laws are being abused to persecute Christians.
"The Pakistani government should reform the laws immediately to protect the lives of Christians and other minorities who have clearly committed no crime."