The liceo classico or ginnasio (lit. 'classical lyceum') is the oldest public secondary school type in Italy. Its educational curriculum spans over five years, when students are generally about 14 to 19 years of age.

Until 1969, this was the only secondary school from which one could attend any kind of Italian university courses (including humanities and jurisprudence), thus being the school where the Italian elite were educated. It is known as a social scientific and humanistic school, one of the very few European secondary school types where the study of ancient languages (Latin and Ancient Greek) and their literature are compulsory. Most of the individuals who achieved the highest levels of leadership in the Italian government, science, diplomacy and business attended the Liceo Classico.

Liceo classico schools started in 1859, with the implementation of Gabrio Casati's reform.

The Gentile Reform implemented the so-called ginnasio, a five-years school comprising middle school (for students from 11 to 16), with a final test at the end of the second year of the secondary school. The test was written and oral, and it was compulsory in order to be admitted to the last three years of liceo. Currently liceo classico is similar to every other liceo in Italy, high school starts at 14 after middle school, without any additional exams.

Since the 1960s, all presbyters and bishops of the Catholic Church studied in seminaries and, since the 1990s, the topics taught inside those seminaries were the same as liceo classico (theoretical philosophy, Latin and Ancient Greek grammar and literature, English), with many others: ethics, psychology, pedagogy, sociology, Hebrew language, biblical criticism, Koine Greek (the Hellenistic period and Septuagint Bible), pastoral theology, Christian ethics and systematic theology, anthropology and eschatology, sacramentarian theology, Christology and Trinitarian theology, Mariology, patristics, ecclesiology, history of Christianity, history of religions, canon law, and liturgy.

The liceo classico school type finds its roots in the so-called liceo ginnasio, established in 1859 with the Casati law, as a school following elementary school (compulsory), initially in force in the Kingdom of Sardinia and then extended to whole Italy after Italian Unification. High schools, however, already existed, having been established during the Napoleonic era, to ensure a high level of education to secular institutions as well.

On the model of the pre-unification humanist scholastic tradition, the Casati law provided for a single lyceum address in which the literary and humanistic subjects were prevalent. The original study plan foresaw an eight-year course (there was no middle school at the time), divided into five years of ginnasio and a three-year liceo ("lyceum"): the study of Latin began in the first gymnasium class, that of the (Ancient) Greek in the third.

The liceo ginnasio was an eight-year secondary school, since it also included middle school. It was accessed after primary school (initially a four-year school) and gave access to university degree courses of any kind; liceo ginnasio was the only secondary course of lyceum type, which was not aimed at technical-professional training, but at the continuation of studies in the university.