Wizards of the Coast (publishers of the Dungeons and Dragons desktop role playing game) have for years operated under the Open Gaming License.

The License: This License applies to any Open Game Content that contains a notice indicating that the Open Game Content may only be Used under and in terms of this License. You must affix such a notice to any Open Game Content that you Use. No terms may be added to or subtracted from this License except as described by the License itself. No other terms or conditions may be applied to any Open Game Content distributed using this License.

More or less, it says WOTC is allowing people to use their mechanisms (i.e. gameplay), as long as they don't use their copyrighted works (i.e. art, named characters, etc.).

A recent firestorm erupted when WOTC seemed poised to update the terms of the license to collect royalties. As one of the OGL creators said at the time

In a 2002 interview, then-WotC VP and OGL architect Ryan Dancey said the OGL was "essentially exposing the standard D&D mechanics, classes, races, spells, and monsters to the Open Gaming community. Anyone could use that material to develop a product using that information essentially without restrictions, including the lack of a royalty or a fee paid to Wizards of the Coast."

Putting aside the controversy over the changes, is the OGL actually a type of Open Source license? Does it qualify as copyleft in any sense?

  • I only had a short look, no proper review… but… it’s probably close. The rights granted are pretty standard for OSS licences, there are no obvious problematic requirements… but the “Product Identity” thing is very broad and possibly limiting. It looks close to the GNU FDL with invariant sections to me… OTOH there are OSS licences that exclude trademarks, so the devil is probably in the wording. Maybe ask the OKFN whether it matches the OKD (which is akin to OSI and OSD, respectively, for nōn-software)?
    – mirabilos
    Jan 19, 2023 at 2:25

1 Answer 1


As per the Help Center, this site uses two resources to guide its definition of whether something is "open source" or not:

These aren't a perfect match for the OGL because they are both somewhat biased towards free software rather than free content in general, but they can still probably act as a good starting point as to whether we think the OGL is "open source" or not.

FSF's Four Freedoms

Freedom 0: The freedom to run the program as you wish, for any purpose

Translating this to something like "the freedom to use the content as you wish, for any purpose", this freedom would seem to me to be satisfied by the OGL Clause 4:

the Contributors grant You a perpetual, worldwide, royalty-free, non-exclusive license with the exact terms of this License to Use, the Open Game Content.

with no conditions attached to that.

Freedom 1: The freedom to study how the program works, and change it so it does your computing as you wish

This freedom is primarily based around the distinction between source and binaries for software; that's a distinction which isn't really relevant for tabletop gaming content.

Freedom 2: The freedom to redistribute copies so you can help others

The OGL's definition of "Use" is (from Clause 1):

"Use", "Used" or "Using" means to use, Distribute, copy [...] Open Game Content.

That freedom would seem to be satisfied.

Freedom 3: The freedom to distribute copies of your modified versions to others

Again from the OGL's definition of "Use":

"Use", "Used" or "Using" means to [...] edit, format, modify, translate and otherwise create Derivative Material of Open Game Content.

That pretty explicitly allows creation of modified versions.

Open Source Definition

Being slightly more terse here:

  1. Free Redistribution: there are no restrictions in the OGL about OGL content being distributed with non-OGL content; in fact, this is very common for OGL content.
  2. Source Code: as per FSF Freedom 1, not really relevant.
  3. Derived Works: as per FSF Freedom 4.
  4. Integrity of The Author's Source Code: not really relevant as this is again about a source/binary distinction.
  5. No Discrimination Against Persons or Groups: nothing of this sort mentioned in the OGL.
  6. No Discrimination Against Fields of Endeavor: nothing of this sort mentioned in the OGL.
  7. Distribution of License: no mention of additional licenses in the OGL.
  8. License Must Not Be Specific to a Product: no mention of specific products in the OGL.
  9. License Must Not Restrict Other Software: even when "translated" to "License Must Not Restrict Other Content", there are no restrictions of this kind in the OGL.
  10. License Must Be Technology-Neutral: no mention of anything of this kind in the OGL.

So, is the OGL "Open Source"?

From the above analysis, the prima facie answer would be "yes". However, one major issue lurks: as noted on the FSF's page, it is absolutely crucial that any open source license is irrevocable, as a license is in many ways not worth anything if all your rights can be removed tomorrow. Is the OGL irrevocable?

The OGL grants "a perpetual, worldwide, royalty-free, non-exclusive license" (Clause 4 again). I'm aware there has been an enormous amount of mostly amateur discussion specifically around the OGL as to whether a perpetual license is in fact irrevocable; that would seem to be a question which we'd only get a real answer on when a court rules in a specific jurisdiction. However, it remains a fact that the leaked draft of the OGL 1.1 did in fact try to revoke the OGL 1.0a, and whatever Wizards of the Coast may be, one thing they certainly do have is some good lawyers - if those lawyers believe it can be revoked, I'd say there's enough uncertainty about it that it could well be.

Therefore my conclusion would be that the OGL is not an open source license.

  • For avoidance of doubt: this is very much posted as a starting point. I am more than open to revising my opinion, both as to whether the OGL satisfies the four freedoms and the OSD and as to the issues around irrevocability if good evidence is provided. Jan 19, 2023 at 13:33
  • OP said in the question "Putting aside the controversy over the changes [in the leaked OGL draft]" so isn't the fact that you're considering the "leaked draft of the OGL 1.1" at the bottom of your Answer a bit unfair? If you consider only the OGL official version itself, then is that "open source" according to your analysis?
    – Brandin
    Jan 20, 2023 at 14:01
  • Also if you're considering future versions of OGL, then please already consider OGL v1 which says in part 9, explicitly: "You may use any authorized version of this License to copy, modify and distribute any Open Game Content originally distributed under any version of this License." I.e. it sounds like people will still be able to choose the old version of the license if they don't like the newer OGL version when it comes out officially.
    – Brandin
    Jan 20, 2023 at 14:08
  • So wouldn't item 9 basically make it irrevocable? I'm no lawyer but point 9 sounds in fact even more generous than the GPL optional clause "or at your option, any later version" which allows people to upgrade from GPLv2 to v3 (but generally not the other way around). The OGL item 9 sounds to me like it allows one even an option to "downgrade" from content published under some later version of OGL and to opt to use an earlier official version (such as v1.0) instead.
    – Brandin
    Jan 20, 2023 at 14:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.