An academic major is the academic discipline to which an undergraduate student formally commits. A student who successfully completes all courses required for the major qualifies for an undergraduate degree. The word major (also called concentration, particularly at private colleges) is also sometimes used administratively to refer to the academic discipline pursued by a graduate student or postgraduate student in a master's or doctoral program.

An academic major typically involves completion of a combination of required and elective courses in the chosen discipline. The latitude a student has in choosing courses varies from program to program. An academic major is administered by select faculty in an academic department. A major administered by more than one academic department is called an interdisciplinary major. In some settings, students may be permitted to design their own major, subject to faculty approval.

In the United States, students are usually not required to choose their major discipline when first enrolling as an undergraduate. In addition, most colleges and universities require that all students take a general core curriculum in the liberal arts. Normally students are required to commit by the end of their second academic year at latest, and some schools even disallow students from declaring a major until this time. A student who declares two academic majors is said to have a double major. A coordinate major is an ancillary major designed to complement the primary one. A coordinate major requires fewer course credits to complete. Many colleges also allow students to declare a minor field, a secondary discipline in which they also take a substantial number of classes, but not so many as would be necessary to complete a major.

The roots of the academic major as we now know it first surfaced in the 19th century as "alternative components of the undergraduate degree". Before that, all students receiving an undergraduate degree would be required to study the same slate of courses geared at a comprehensive "liberal education".

In 1825, the University of Virginia initiated an educational approach that would allow students to choose from an area of focus. Offering eight options (which included ancient languages, anatomy, medicine), other higher educational systems in Europe began to develop into a stricter specialization approach to studies after the American Civil War.

In the United States, in the second half of the 19th century, concentrated foci at the undergraduate level began to prosper and popularize, but the familiar term "major" did not appear until 1877 in a Johns Hopkins University catalogue. The major generally required 2 years of study, while the minor required one.

From 1880 to 1910, Baccalaureate granting American institutions vastly embraced a free-elective system, where students were endowed with a greater freedom to explore intellectual curiosities.

The 1930s witnessed the appearance of first interdisciplinary major: American studies. Culture was the grounding concept and orchestrating principle for its courses. 1960s to 1970s experienced a new tide of interdisciplinary majors and a relaxation of curriculum and graduation requirements. (Civil Rights Movement spawned Women's studies and Black Studies, for example.) In the 1980s and 1990s, "interdisciplinary studies, multiculturalism, feminist pedagogy, and a renewed concern for the coherence and direction of the undergraduate program began to assail the Baccalaureate degree dominated by the academic major."