Academic freedom is a moral and legal concept expressing the conviction that the freedom of inquiry by faculty members is essential to the mission of the academy as well as the principles of academia, and that scholars should have freedom to teach or communicate ideas or facts (including those that are inconvenient to external political groups or to authorities) without fear of repression, job loss, or imprisonment. While the core of academic freedom covers scholars acting in an academic capacity — as teachers or researchers expressing strictly scholarly viewpoints —, an expansive interpretation extends these occupational safeguards to scholars' speech on matters outside their professional expertise. Especially within the anglo-saxon discussion it is most commonly defined as a type of freedom of speech, while the current scientific discourse in the Americas and Continental Europe more often define it as a human right with freedom of speech just being one aspect among many within the concept of academic freedom.

Academic freedom is a contested issue and, therefore, has limitations in practice. In the United States, for example, according to the widely recognized "1940 Statement on Academic Freedom and Tenure" of the American Association of University Professors, teachers should be careful to avoid controversial matters that are unrelated to the subject discussed. When they speak or write in public, they are free to express their opinions without fear from institutional censorship or discipline, but they should show restraint and clearly indicate that they are not speaking for their institution. Academic tenure protects academic freedom by ensuring that teachers can be fired only for causes such as gross professional incompetence or behavior that evokes condemnation from the academic community itself.