As Nonsuch is a grammar school, girls are required to take the 11+ exam to gain entry into year 7, which used to be a shared selection test with Wallington High School for Girls, but was made separate in 2009, and then in 2016 they were recombined. However, there are sometimes additional places in other year groups, and these are allocated based on tests in English, Mathematics and Science. There is another intake for the sixth form, which is based on GCSE results. An average points score of 50 points and a grade B or above in GCSE Mathematics and English Language is needed for this.