Dungeon Masters Guild (officially abbreviated DMs Guild) is a program through which third-party developers and publishers can sell products that use the official Dungeons & Dragons 5th Edition rules. DMs Guild is also the official web store for buying digital copies of Wizards of the Coast-published Dungeons & Dragons books of all editions.
Products in the DMs Guild program can use the entirety of the D&D 5th edition rules (including the Forgotten Realms and Ravenloft campaign settings), can be sold directly through the official D&D web store at dungeonmastersguild.com and may potentially receive marketing from Wizards of the Coast, the publisher of Dungeons & Dragons. In exchange, the publisher surrenders all copyright to the work to Wizards of the Coast, and Wizards receives the majority of the product's sales revenues. Additionally, Wizards or any other DMs Guild publisher may reprint any portion of any work published under the DMs Guild program without notifying or compensating the original publisher.
All products published via DMs Guild must follow not only the content guidelines laid out in the DMs Guild license agreement but also the community content guidelines for OneBookShelf, the company that operates the DMs Guild web store. All OneBookShelf accounts (including DMs Guild, DriveThruRPG and RPGNow) share the same library, so products purchased on different OBS sites will all be placed into the same library, provided that they are purchased using the same account. Prior to the launch of the DMs Guild program, the Dungeons Masters Guild web store was known as dndclassics.com, and sold digital books from all versions of Dungeons & Dragons up through 5th Edition. These older products are still available, with more added each week; only the website's name and branding have changed.
Third-party publishers are not required to participate in the DMs Guild program to publish third-party 5e products; they can instead use the 5e System Reference Document to publish under the Open Game License, but can only use the rules in the SRD and may not sell their products through the DM Guild web store. However, publishers who don't use the DM Guild do not surrender their copyright to Wizards and are not required to give any portion of their sales revenues to Wizards; instead, the product is covered by all protections found in the OGL. Digital products that use the OGL and SRD rather than the DMs Guild program can not publish under the DMs Guild website, but are otherwise not restricted in their choice of storefronts (including DriveThruRPG), whereas publishers under DMs Guild may only publish digitally via the DMs Guild web store.