A sixth form college is an educational institution in England, Wales, Northern Ireland, Belize, The Caribbean, Hong Kong, Malta, Norway, etc, where students aged 16 to 19 typically study for advanced school-level qualifications, such as A-levels, or school-level qualifications such as GCSEs. In Singapore and India, this is known as a junior college. The municipal government of the city of Paris uses the word "sixth form college" as the English name for a lycée.

In England, The Caribbean, and Wales, education is only compulsory until the end of year 11, the school year in which the pupil turns 16 (although this is changing in August 2013 to compulsory education until year 12 and by 2015, education will be compulsory until year 13) In the English and Welsh state educational systems, those wishing to continue may either stay on at a secondary school with an attached sixth form, transfer to a local sixth form college, or go to a more vocational further education college, although, depending on geographical location, there may be little choice as to which of these options can be taken. In the independent sector, sixth forms are an integral part of secondary schools (public schools), and there is also a number of smaller-scale independent sixth form colleges.

In the education systems of England, Wales, and Northern Ireland, and of Commonwealth West Indian countries such as Barbados, Trinidad and Tobago, Belize, Jamaica and Malta, sixth form (sometimes referred to as Key Stage 5) represents the final two years of secondary education, where students (typically between sixteen and eighteen years of age) prepare for their A-level (or equivalent) examinations.

The first five years of English secondary schooling were previously known as forms. Pupils started their first year of secondary school in the first form or first year, and this was the year in which pupils would normally become 12 years of age. Pupils would move up a form each year before entering the fifth form in the year in which they would have their sixteenth birthday. Those who stayed on at school to study for A-levels moved up into the sixth form, which was divided into the Lower Sixth and the Upper Sixth. In some private schools, the term Middle Sixth was used in place of Upper Sixth, with the latter being used for those who stayed on for an extra term to take the entrance examinations that were previously set for candidates to Oxford or Cambridge universities. Other schools described these Oxbridge examination students as being in the Seventh Form or Third Year Sixth.