Does Gaseous Form protect you from the effects of Entangle, Web, other similar spells, or actions like Grapple?

I know how I'd rule in my game, but is there an official answer?

I mean, nothing is explicitly said regarding the interactions between those: Entangle has no exception for incorporeal, or gaseous, creatures, and Gaseous Form does not specify it makes you immune to those types of effects... but it does say you can pass through "mere cracks", and the space between vines and whatnot in Entangle, and between fingers, or arms, of a Grappler, is certainly more than "mere cracks"...

I would rule that those spells don't stop a creature under the affect of Gaseous Form. However, I do not know if there is an "official" answer to this.

With a quick search, I see no official address to this specific situation in errata, compendium, or JC's tweets. It doesn't surprise me, though, to be honest.

This seems like an ideal case where DM adjudication comes to play. Gaseous Form doesn't directly reference grappling, nor does it give immunity to speed reductions or the restrained condition, such as Freedom of Movement. At the same time, it doesn't turn you completely intangible (nonmagical attacks can still hurt you, even if you have resistance to them), so you can still be targeted (and affected) by attacks.

No clearly dictated interaction, so... DM decision.

Personally, I think it's so that the source of the effect comes to play. Tentacles trying to grapple the mist will likely fail automatically, but a telekinetic effect that restraints may not, and a wind effect that reduces movement or checks may even be more effective.

I like those little things that make circumstances more nuanced and interactions more alive than a video game. :)

If you want to go by the book, the person in Gaseous Form gets advantage on the Strength or Dexterity saving throws.  That's the only point where they seem to interact mechanically.

But this seems like the kind of thing that's going to fall under the purview of the DM.  One may decide that magically generated vines or webs may in fact still impede the target, but others may deem it an automatic failure, regardless of the nature.  "Rule of Cool" may also come into play...

Being incorporeal means that you're both in the astral (or other) plane and the material plane. That is why monsters like the specter and ghost can move through things as if they're difficult terrain. If they were not influenced by the material plane at all, this would not be the case.

So RAW, yes those spells influence incorporeal beings. As you've stated with gaseous form though, this would not hold them due to the fact that the spell allows you to slip through cracks, this is where the advantage to saving throws come in. As JediShadow stated, the rule of cool applies and magic vs magic is always a bit odd in these cases. As a DM you could rule things differently, I'd rule it as magic vs magic so it actuyally would be able to grasp the gaseous person (applying the advantage as normal)

hope this helps