Copyright infringement and plagiarism are related but distinct concepts. Copyright prohibits certain uses of original works of authorship without permission. Plagiarism norms prohibit copying certain expressions, facts, and ideas without attribution. The prevailing theory of copyright is the economic theory, which holds that copyright is justified because it is economically efficient. This article considers whether academic plagiarism norms are economically efficient. It concludes that academic plagiarism norms prohibiting non-copyright infringing plagiarism are not efficient and should be ignored.