The Spanish Baccalaureate (Spanish: Bachillerato, pronounced [baʧiʎeˈɾato] ^ⓘ) is the post-16 stage of education in Spain, comparable to the A Levels in England, Wales and Northern Ireland, Highers in Scotland, the French Baccalaureate in France or the International Baccalaureate. It follows the ESO (compulsory stage of secondary education). After taking the Bachillerato, a student may enter vocational training (Higher-level Training Cycles, Ciclos Formativos de Grado Superior) or take the "PAU" (also commonly known as "PEvAU" or "Selectividad") exams in order to be admitted into a public university.

There are two parts, a core curriculum with the compulsory subjects ("fase de acceso") and a specialist part ("fase de admisión") with a number of pre-selected branches to choose from. The latter of these is technically optional, however reaching the necessary grade is significantly harder or impossible to achieve.

In Spanish (and Hispano-American) education from the 13th century up to the 17th or 18th century, the term Bachiller referred to the lower grade of university studies, enabling entry to a profession without reaching the higher grades of licenciado or doctorado.

Before 1953 in Spain, the term bachillerato covered all of secondary education, which was taken after passing an entrance examination by those students expected to go to university. It consisted of seven yearly stages, normally taken between the ages of 10 and 17. On completion, students took a State Examination (Examen de Estado). From 1949 there was also a vocational or technical version (Bachillerato Laboral).

In 1953 the bachillerato was divided into two parts: Bachillerato Elemental (elementary) and Bachillerato Superior (higher). The first was taken over four years, at ages 10–14, and the second over two years at 15 and 16; each stage terminated with a final examination (Reválida). Students who had remained in primary education up to the age of 14, on passing the first-stage Reválida, could still enter the Bachillerato Superior, in which there were two branches: Sciences and Arts. Following this, students could take a one-year stage of pre-university studies (Preuniversitario, or "Preu" for short).

Reforms during the 1970s absorbed the Bachillerato Elemental into the upper stages of the basic education system for 6- to 14-year-olds, and replaced the Bachillerato Superior with a three-year Bachillerato Unificado Polivalente (BUP). At the age of 14 a student could now opt to enter the BUP without having to pass a specific test, or could go into vocational training. The "Preu" was replaced by a Curso de Orientación Universitaria (COU).

The introduction under "LOGSE [es]" of compulsory secondary education up to age 16 (Educación Secundaria Obligatoria, ESO) took place during the 1990s. The Bachillerato now became a two-year course following the completion of compulsory education, with middle-grade vocational training as an alternative. It had five branches: Arts, Technology, Social Sciences, Health Sciences, and Humanities. Further reforms were made under the "LOE [es]" of 2006, and under the "LOMCE [es]" of 2013.

As established under LOE (the Spanish Educational Law) of 2006, the Baccalaureate is studied over two years, usually upon the completion of compulsory secondary education (ESO). Following the enactment of LOMCE, there are four distinct branches: Arts (two paths), Sciences and Technology, Humanities and Social Sciences (with two "itineraries" for the Humanities and Social Sciences branch) and General.