This guide explains how discovery actually works in the inter partes proceedings—oppositions and cancellations—that the Trademark Trial and Appeal Board decides inside the U.S. Patent and Trademark Office. It maps the three layers of governing authority: the Federal Rules of Civil Procedure, the Board's own regulation at 37 C.F.R. § 2.120, and the Trademark Trial and Appeal Board Manual of Procedure, and it states the rules as amended in 2017 so readers avoid the outdated numbers still floating in old form files. Device by device, it covers interrogatories, requests for production, requests for admission, and depositions, each with its post-2017 caps, response clock, and Board-specific quirks, along with the mandatory discovery conference, front-loaded initial disclosures, the unforgiving thirty-one-day service window, motions to compel, sanctions, and disclosure estoppel. Because the Board decides every case on a paper record, the guide treats discovery as the trial itself and shows how to aim each request at the ground in play—likelihood of confusion under the DuPont factors, priority, descriptiveness, abandonment, or fraud. Worked hypotheticals, model requests, governing case law, and inline cross-references to related UpLaw resources round out a research-grade treatment for practitioners, business owners, and self-represented parties.