Does your choice of a Cleric subclass at 3rd level have to match the domain/portfolio options offered by your deity?

Coming from previous editions of D&D and Pathfinder, I know the answer to this question is "yes".

Just not sure of the answer in the latest edition (2024 D&D). For instance, the gods listed in the 2024 DMG for Greyhawk don't seem to have domain options listed (unless it's listed someplace I haven't looked).

The choice of what deities exist, what domains they are associated with, and what subclasses clerics devoted to them can pick is really up to the DM.

Quote from wagnarokkr >>

The choice of what deities exist, what domains they are associated with, and what subclasses clerics devoted to them can pick is really up to the DM.

I see. Was hoping there might be more guidelines for this sort of thing, but it at least answers my question. Thanks!

The normal answer is Yes, clerics choose from the Diety's available domains (in 5e is mostly 1, but since 3rd party and subclasses some gods have access to more).

But dieties are really part of the world/setting you are playing so as wagnarokkr says, those definitions are purely dm dependant.

Also, there could be background or story beats that could make you choose a non-available domain for a diety, again very dm dependant but just to put that choice out there.

My interpretation of which domain(s) ought to be assigned to a deity, is largely determined by the overall goals of that deity or its perceived audience of worshippers. For instance, in Heroes of Faerun, Gond is listed as being the deity of artisans and crafts persons and to be allied with Oghma. For this reason, I plopped Oghma, Gond and Milil (deity of bards and poets) in the Knowledge domain. The Scribe of Death, Jergal, is in both Knowledge.and Apocalypse domains. Granted, Your Mileage May (and probably will) Vary, but aligning the domain with the deity's stated goals is usually best.

It does say (somewhere) that any deity can be a patron of Life, but beyond that...

I think if you can justify it to your DM with lore, E.G. "Vecna is a very violent, angry person, you could call him tempestuous! And given he was a wizard he can probably use lightning magic, so can I be a Tempest Cleric?" then it should be fine. It's just story, not much mechanical impact.

Quote from EdgohSaile >>

It does say (somewhere) that any deity can be a patron of Life, but beyond that...

I think if you can justify it to your DM with lore, E.G. "Vecna is a very violent, angry person, you could call him tempestuous! And given he was a wizard he can probably use lightning magic, so can I be a Tempest Cleric?" then it should be fine. It's just story, not much mechanical impact.

 Any deity can have the Life domain.........I have my doubts about Asmodeus, Shar, Umberlee and Malar, for example.