An academic minor is a college or university student's declared secondary academic discipline during their undergraduate studies. As with an academic major, the college or university in question lays out a framework of required classes or class types a student must complete to earn the minor—although the latitude the student is given changes from college to college. Academic minors and majors differ in that the former is subordinate to the latter. To obtain an academic minor, a total of three years of study at a university in a selected subject is the usual requirement.
Some students will prepare for their intended career with their major, while pursuing personal interests with a minor. For example, some students may major in civil engineering and minor in a foreign language.
Other students may pursue a minor to provide specific specialization and thus make themselves more attractive to employers. It is not infrequent for a physics major to minor in computer science or an economics major to minor in mathematics. Engineering students frequently take a minor in mathematics, as they already have most course credits needed for the purpose.
At some point, a minor may be the foundation for a career. For example, students intending to become secondary education teachers often major in their teaching subject area (for example, history or chemistry) and minor in education.
Additionally, a minor may be used to pursue an alternative interest. The same engineering student may decide to minor in performing arts.
In 1910, A. Lawrence Lowell, president of Harvard, "introduced a system that required students to major in a subject and also to take courses outside their areas of concentration." Harvard University itself, however, does not offer undergraduates the option of taking a minor, but rather "a secondary field, similar to a minor at many schools."  Australia also offers double majors and minors. However, in other countries, like the United Kingdom, students usually focus on a single area of study. In Quebec, most francophone universities do not use the minor/major structure. Single-year programs are known as certificates and may be combined with other programs to form a bachelor by accumulation (known as a baccalauréat par cumul).
While academic minors are usually associated with undergraduate degrees as a student's secondary focus, academic minors also exist at the graduate level, particularly in U.S. institutions. Sometimes this can refer to a student's minor or secondary field within their discipline, such as a Political Science PhD student pursuing a major field in American Politics and a minor field in Political Theory, or a Religious Studies PhD student pursuing a major field in Theology and a minor field in History of Religion.
However, as in undergraduate courses of study, outside graduate study minors also exist at many universities - sometimes officially and sometimes unofficially. For example, at Oregon State University, Master's and PhD students are able to pursue an official graduate minor in addition to the discipline of their degree. At Florida State University, graduate minors exist on an unofficial basis on the grounds that a Master's or Doctoral student takes at least 9 and at most 18 credit hours in a secondary field outside of his or her academic discipline. Typically, an outside minor at the maximum allowed credit hours or quarter credit units (typically 18 credit hours in many public universities, or 24 credit units at others) fulfills a qualifying requirement to teach the discipline as an adjunct at a community college or state college, and the research experience and connections from an outside minor can also be tailored toward pursuing a non-academic career related to the minor field. Some PhD students, pursuing an outside graduate minor, choose to integrate the minor field into their dissertation with a scholar from their minor field serving as an outside committee member on their dissertation.
- Charles McGrath, "What Every Student Should Know", New York Times Education Life, January 8, 2006.
- Harvard University, "Setting the Course of Your Degree", Harvard University Fields of Study.
- Kiki Barnes, "Poll: Undergrads say U. should offer minors", Browth Daily Herald University News, April 10, 2013.