Middle School and Junior High School are levels of schooling between elementary and high schools. Most school systems use one term or the other, not both. The terms are not interchangeable. In China, Taiwan, Hong Kong, and Vietnam, the term middle school is used as a synonym for secondary school.^{[clarification needed]}

In Algeria, a middle school includes grades 6 through 9, consisting of students from ages 10 or 11 to 13 to 14.

In Egypt, middle school precedes high school. It is called the preparatory stage and consists of three phases: first preparatory in which students study more subjects than primary with different branches.For Instance, Mathematics is divided into Algebra and Geometry. In second preparatory students study Science, Geography, the History of Egypt starting with Pharonic history, passing by the Coptic, Islamic and finally the modern history, Also they study three different languages, Arabic is obligatory; two others are chosen as first and second languages: English, French, German, Spanish, and Italian. They study also Mathematics. Middle School (Preparatory Stage) lasts for three years. Students are given an overview about future fields of studies.