Marlborough College's admissions process is structured to ensure a comprehensive evaluation of each applicant, beginning with registration up to five years prior to entry, typically starting in Year 9 (13+). The school advises early registration due to high demand, with assessments primarily conducted in Year 6, where around 70 percent of places are allocated. Selection criteria include references from current schools, ISEB pre-test results, and interviews, focusing on not just intellectual ability but also character, creativity and energy. For those entering the sixth form, competition is intense, with applicants needing a minimum of six GCSEs at grade 6 or above, and specific grades in relevant subjects for A level studies. Marlborough College also values diversity, with a significant proportion of its student body coming from over 260 prep schools across the UK and internationally, contributing to its global community ethos.