A diploma (from Greek δίπλωµα. díplōma, meaning "folded paper") is a certificate or deed issued by an educational institution, such as a university, that testifies that the recipient has successfully completed a particular course of study or confers an academic degree. In countries such as the United Kingdom and Australia, the word diploma refers to a level of academic award. The words diplomat and diplomacy have the same origin, from the official "folded papers" of accreditation delivered by ambassadors or delegates.

In some countries, such as the UK and Australia, such a document can be called a testimonium or testamur, Latin for "we testify" or "certify" (testari), and so called from the word with which the certificate begins. In Ireland, it is generally called 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).

PLC or plc may refer to: