A diploma is a certificate or deed issued by an educational institution, such as college or university, that testifies that the recipient has successfully completed a particular course of study. The word diploma also refers to an academic award which is given after the completion of study in different courses such as diploma in higher education, diploma in graduation or diploma in post graduation etc. Historically, it can also refer to a charter or official document, thus diplomatic, diplomat and diplomacy via the Codex Juris Gentium Diplomaticus.

The diploma (as a document certifying a qualification) may also be called a testamur, Latin for "we testify" or "certify" (testari), so called from the word with which the certificate begins;this is commonly used in Australia to refer to the document certifying the award of a degree.Alternatively, this document can simply be referred to as a degree certificate or graduation certificate, or as a parchment. The certificate that a Nobel laureate receives is also called a diploma.

The term diploma is also used in some historical contexts, to refer to documents signed by a King affirming a grant or tenure of specified land and its conditions (see Anglo-Saxon Charters and Diplomatics)