Encyclopaedia Britannica has sued OpenAI in a United States federal court, accusing the firm of using its content without permission to train its artificial intelligence systems.
The lawsuit, filed on March 13, 2026 at the U.S. District Court for the Southern District of New York, claims that OpenAI copied close to 100,000 articles from Britannica and its dictionary arm, Merriam-Webster.
According to the complaint, this material was used to train large language models behind ChatGPT.
Britannica says the chatbot can produce responses that are so close to its original entries. It argues that this reduces visits to its own platforms, as users rely on AI-generated summaries instead of going directly to its website.
The company also alleges trademark misuse, stating that its name is sometimes cited in responses in ways that suggest approval where none exists.
In response, OpenAI said its systems are built using publicly available data and operate within the bounds of fair use. A spokesperson said, “Our models empower innovation, and are trained on publicly available data and grounded in fair use.”
Britannica has not publicly expanded on the case since filing. Its representatives did not respond to follow-up questions at the start of the week.
This case adds to other legal disputes involving AI developers and content owners. Over the past year, publishers, authors and artists have challenged how their work is used in training data.
Similar claims have also been brought against other firms, including an ongoing case between Britannica and Perplexity AI, filed in 2025.
Questions including whether using copyrighted material to train AI systems qualify as fair use, have been asked. Technology companies say the process transforms the material into something new, but Publishers disagree, arguing it amounts to copying without consent.
