Key Stage 3 (commonly abbreviated as KS3) is the legal term for the three years of schooling in maintained schools in England and Wales normally known as Year 7, Year 8 and Year 9, when pupils are aged between 11 and 14. In Northern Ireland the term also refers to the first three years of secondary education, although these are known as Year 8, Year 9 and Year 10.

The term is used to define the group of pupils who must follow the relevant programmes of study from the National Curriculum. All pupils in this Key Stage must follow a programme of education in at least 15 areas:

Information about the current KS3 curriculum in Wales can be found here.

A new curriculum for Wales will be developed with education professionals across Wales with the aim of it being available to settings and schools by September 2018.  Further information can be found here.