Adapted from the ninth edition of the MLA Handbook. Read an adapted version of the guidelines in Spanish.

Occasionally an author or public speaker is accused of plagiarism. No doubt you have had classroom conversations about plagiarism and academic dis­honesty. Your school may have an honor code that addresses academic dis­honesty; your school almost certainly has disciplinary procedures meant to address plagiarism. But you may not be sure what exactly this offense is and how to avoid committing it.

What Plagiarism Is and Why It’s a Serious Matter

Plagiarism is presenting another person’s ideas, words, or entire work as your own. Plagiarism may sometimes have legal repercussions (e.g., when it involves copyright infringement) but is always unethical.

Plagiarism can take a number of forms. Copying a published or unpub­lished text of any length, whether deliberately or accidentally, is plagiarism if you don’t give credit to the source. Paraphrasing someone’s ideas or argu­ments or copying someone’s unique wording without giving proper credit is plagiarism. Turning in a paper or thesis written by someone else, even if you paid for it, is plagiarism.

It’s even possible to plagiarize yourself. In published work, if you reuse ideas or phrases that you used in prior work and do not cite your prior work, you have plagiarized. Many schools’ academic honesty policies prohibit the reuse of one’s prior work in papers, theses, and dissertations, even with self-citation. (Sometimes, however, revising and building on your earlier work is useful and productive for intellectual growth; if you want to reuse portions of your previously written work in an educational context, ask your instructor.)

When writers and public speakers are exposed as plagiarists in profes­sional contexts, they may lose their jobs and are certain to suffer public embarrassment, diminished prestige, and loss of credibility. One instance of plagiarism can cast a shadow across an entire career because plagiarism reflects poorly on a person’s judgment, integrity, and honesty and calls into question everything about that person’s work. The consequences of plagia­rism aren’t just personal, however. The damage done is also social. Ulti­mately, plagiarism is serious because it erodes public trust in information.

Avoiding Plagiarism

To read our guidelines about avoiding plagiarism, see 4.2–4.11, freely available sections on MLA Handbook Plus, the only authorized subscription-based digital resource featuring the MLA Handbook, available for unlimited simultaneous users at subscribing institutions.