Secondary education covers two phases on the ISCED scale. Level 2 or junior secondary education is considered the second and final phase of basic education, and level 3 (Upper) secondary education is the stage before tertiary education. Every country aims to provide basic education, but the systems and terminology remain unique to them. Secondary education typically takes place after six years of primary education and is followed by higher education, vocational training or employment. In most countries it is compulsory for students between the ages 11 and 16. Compulsory education sometimes extends to age 19.

Since 1989 education has been seen as a basic human right for a child, article 28, of the Convention on the Rights of the Child states that: primary education should be free and compulsory while different forms of secondary education, including general and vocational education, should be available and accessible to every child. The terminology has proved difficult- and there was no universal definition before ISCED, divided the period between primary education and university into junior secondary education and (upper) secondary education.

In classical and mediaeval times secondary education was provided by the church for the sons of nobility and to boys preparing for universities and the priesthood. As trade required navigational and scientific skills the church reluctantly expanded the curriculum and widened the intake. With Comenius and Joseph Locke- education changed from being repetition of Latin text, to building up knowledge in the child- and with the Reformation the state wrestled the control of learning from the church. Education was for the few. As late as 1868, secondary schools were organised to satisfy the needs of different social classes with the labouring classes getting 4yrs, the merchant class 5yrs and the elite getting 7 years. Only then did it become accepted that girls could be sent to school. The rights to a secondary education were codified after 1945, and countries are still working to achieve the goal of mandatory and free secondary education for all youngsters under 19.
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