A secondary school is a school for students roughly between ages 11 and 18, the years after elementary school and before college. In the United States, secondary schools are typically divided into middle school (or junior high school) for younger students and high school for older students. In many other countries, students attend a single secondary school for all these years.

The word “secondary” means “second in order,” showing that this education comes second, after primary or elementary school. Different countries organize secondary schools differently. In Britain, students might attend a “grammar school” or “comprehensive school.” In Germany, students go to a Gymnasium or Realschule. In Japan, students attend chūgakkō (middle school) and kōtōgakkō (high school).

Secondary school is where students start studying subjects in greater depth: instead of one teacher teaching everything, students have different teachers for math, science, history, and languages. The work becomes more challenging as students prepare either for college or for entering the workforce. In most countries, attending secondary school is required by law, though the exact ages and rules vary by location.