A pupil at Aylesbury High School says she was 'shocked' after scoring 162 - the highest number possible - on the Mensa IQ test.
Tara Sharifi, 11, scored 162 points - meaning she is well above the so-called 'genius benchmark' of 140.
Her score is also two points higher than the estimated IQs of physicist Albert Einstein and cosmologist Professor Stephen Hawking.
Tara said: "I was shocked when I got the result - I never expected to get such a good score."
Tara took the test in Oxford and had to answer questions within a set time.
It was a non-verbal test which focused on Tara's ability to understand the meanings of words.
Tara said: "It was a joint decision between me and my parents to take the test.
"It will be a wonderful opportunity to meet other people within the Menza system."
Tara now qualifies for membership of Mensa, also known as the High IQ society and says she looks forward to meeting other members of Mensa at some of the organisation's gatherings.
She added: "I have told some of my friends at school and they were really impressed.
"When I am older, I would like to do something related to mathematics."
Her dad Hossein added: "I am extremely proud but very surprised at how well Tara scored.
"I figured she might do well when we watched TV and she would get maths questions before the contestants.
"I knew she was very clever but I did not think she would have such a high IQ."