A diploma mill (also known as a degree mill) is an organization that awards academic degrees and diplomas with substandard or no academic study and without recognition by official educational accrediting bodies. The purchaser can then claim to hold an academic degree, and the organization is motivated by making a profit. These degrees are often awarded based on construed life experience. Some such organizations claim accreditation by non-recognized/unapproved accrediting bodies set up for the purposes of providing a veneer of authenticity.

While the terms "degree mill" and "diploma mill" are commonly used interchangeably, within the academic community a distinction is sometimes drawn:

Medical diploma mills have operated, and have been blacklisted, in the United States for over 120 years.

Diploma mills are frequently named to sound confusingly similar to those of prestigious accredited academic institutions. Despite the fact that trademark law is intended to prevent this situation, diploma mills continue to employ various methods to avoid legal recourse. Several diploma mills have adopted British-sounding names, similar but not identical to the names of legitimate universities, apparently to take advantage of the United Kingdom's reputation for educational quality in other parts of the world. Some examples of British-sounding names used by diploma mills are "Shaftesbury University", "University of Dunham", "Redding University", and "Suffield University".