Skip to Main Content

Substantial Similarity

Illustrates the "substantial similarity" doctrine from U.S. copyright law, using a set of case summaries.

Copyright Questions?

The University of Michigan Library Copyright Office provides help with copyright questions for University of Michigan faculty, staff and students. Please email us with questions or visit our website for more information.

Legal Advice

The information presented here is intended for informational purposes and should not be construed as legal advice. If you have specific legal questions pertaining to the University of Michigan, please contact the Office of the General Counsel.

If you require legal advice in your personal capacity, the lawyer referral services operated by the Washtenaw County Bar Association and the State Bar of Michigan may be helpful to you.

Substantial Similarity

Welcome to the Substantial Similarity guide from the University of Michigan Library Copyright Office.

This guide focuses on the copyright doctrine of substantial similarity. Substantial similarity is a level of similarity that shows improper appropriation of the plaintiff’s work, one of the requirements for a prima facie infringement claim. If the similarity of the defendant’s work to protectable elements in the plaintiff’s work is minimal, or if similarity only exists with regard to unprotectable elements of the work, then there is no substantial similarity. For an introduction to copyright, please see our guide to Copyright Basics

The guide contains summaries of the following cases, along with a glossary of key terms:

The case summaries and glossary were initially written by research assistant Yuanxiao Xu. Quotes within the summaries are from the case summarized, unless otherwise noted. This guide was last revised on February 9, 2018.