The sixth form in the English education system is the term used to refer to the final two years of secondary schooling (when students are about sixteen to eighteen years of age), during which students normally prepare for their GCE A-level examinations.

The first five years of English secondary schooling used to be referred to as years one (in which pupils would have their twelfth birthday) to five (in which they would have their sixteenth). The last two years of schooling, which are non-compulsory, are generally referred to as the sixth form as a relic of this older numbering system, divided into lower sixth and upper sixth, meaning years twelve and thirteen, respectively. In many private schools, the term middle sixth was used in place of upper sixth, with the latter being used as for those remaining on in the last term to take entrance examinations that were previously set for candidates to Oxford or Cambridge. The modern numbering system in fact begins with Primary Education, "Year One" actually referring to the second year of schooling (the first being referred to as "Reception").

In some parts of the country, special "sixth form colleges" were introduced during the decades from 1960 onwards, recognising this as a particularly important phase of student life. A large proportion of English secondary schools no longer have an integral sixth form.

In some secondary schools in Hong Kong, the sixth and seventh year are called Lower and Upper Six(th).

See also: School years (United Kingdom)