Results for Dr Challoners High School have been described as 'excellent' by the headteacher.
At the girls grammar in Little Chalfont, 36.7 per cent of pupils attained at least three A grades and 9.4 per cent achieved four As. In all, 84 per cent of exams were passed at A or B grade. Headteacher Peg Hulse said: "We are delighted with the results; it's another excellent year."
Mary Sharp, director of the sixth form, said: "We are absolutely delighted for our girls to have achieved these results. It's not just about girls coming out with four As, it is about girls who have developed throughout their time at the school."
Stephanie von Kutzleben, 18, of Amersham, gained As in biology, chemistry, maths and further maths - she taught herself the latter.
She said: "I decided to drop French and I was given further maths AS as an extra and I enjoyed it so much that I decided to carry on and teach myself.
"I can't believe I got four As; I didn't think the exams went very well at all. I am going to Warwick University to study biomedical sciences."
Her mother, Jacqueline, said: "I am a very proud mum - it's unbelievable."