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.