I would say yes as it is more powerful than wish.

Quote from Gehennaheretic >>

It's a shame it has to be a willing target. Hit an Elder Brain with this and cut it off from all its telepathic contact. 

 Persuade the hell out of it first !

Disappointed that this spell isn't available to sorcerers, even though we can take Intellect Fortress. Only reason I can think for this being the case is that with Mind Blank working on targets other than yourself that means you could Twinned Spell it?

But I feel like sorcerers lose an awful lot of spells on that basis, considering 8 sorcery points to have Mind Blank affect two targets doesn't seem OP to me.

Quote from VigoBronzebeard >>

 

Cantrip	True Strike	Divination

finally a counter to true strike, that cantrip was waay too op

Quote from VigoBronzebeard >>

1. Mind Blank makes you immune to Divination spells. You are unaffected by them - They fail to gleam information from you (e.g. the True Seeing spell doesn't reveal your invisibility) but also you can't gain their benefits (e.g. you can't cast True Seeing on yourself). 

Level	Spell immunity	Reason
4	Arcane Eye	Divination

Please keep in mind that Arcane Eye does not target or affect creatures.

You are immune to divination spells.

The light that bounces off of you does not acquire that immunity.

The trees that photosynthesize that light do not acquire that immunity.

The houses built from those trees do not acquire that immunity.

EDIT: There's also the part about immunity to spells and effects that are used to gain information about the target. Then again, no matter how immune I am to a microphone/camera, that doesn't stop it from recording my voice/image. Hard to say on that particular part.

EDIT2: It's a little more clear now. Consider the following spell, which explicitly blocks perception of the target through scrying sensors (like arcane eye) https://www.dndbeyond.com/spells/nondetection. This means that the rules support selectively scrubbing someone out of a an image for particular observers, even if the subject is not targeted by that observer. If the rules do indeed account for indirect effects like that, it's very likely that this spell protects from Arcane Eye.

Polymorph, True Polymorph, Greater Restoration, Dispel Magic, unreleased/homebrew spells may be foiled by Mind Blank if they'd otherwise affect a target's mind depending on dungeon master's approval

edit: 6th level Heal on 8th level Feeblemind; the order matters: target fails Feeblemind, Mind Blank is then cast on them so Heal, Greater Restoration and Wish are foiled thanks to the spell's specificity

Good catch! As these substitute the target's mental stats. Then also Mass Polymorph belongs on this list: https://********/spells.html#mass polymorph_xge

I updated the table.

Really feel like this should be called Mind Shield. Mind Blank sounds like an offensive spell that wipes someone’s memory.

I read that some npc in the Strahd book polymorphs under mind blank or may be shape shifting

it does not directly target the mind

also dispel magic isnt foiled since it targets the spell or effect not the mind

Yep. Tthat  counts as divining information about a target

This is probably the best defensive spell in the game. 

Quote from OKMindFlayer1000 >>

Quote from Wraethrax >>

So, I just opened up this option as a 15th level Bard.  I'm liking the idea of casting this at the start of every day to offset my terrible WIS save and the fact we go up against a lot of charmers and charm effects.  Does this seem like a worthwhile idea?

 

 

 

Beyond 20

 

 

 

 

 

 sure just nab magical secrets cast this take a long rest and you got perma imunity

 No need, Mind Blank is a bard spell by default. 

 spells or effects of similar power used to affect the target's mind or to gain information about the target.

I would argue this Line RAW and RAI says it would. But as aslways DM has final say

No, it only affects the mind not illusions, invisibility, etc. It does not somehow cancel out True Sight and bolster an invisibility or illusion spell. So when it says it protects against divination, that doesn't mean it blocks someone from being seen but rather protects the target against having their mind/intentions read to predict their future actions (go back and read the spell description for divination).

Quote from PuzzlingCipher >>

I just realized...this might protect you from the Eye & Hand of Vecna

 

 

Beyond 20

 

 

 

 

 

 OMG that would be crazy.

I understand that Staggering Smite does O psychic damage to a creature under the effects of Mind Blank. What about the other effects of the spell?
Would those effects still apply? 

Quote from KillaJake99 >>

I'm understand that Staggering Smite does O psychic damage to a creature under the effects of Mind Blank. What about the other effects of the spell?
Would those effects still apply? 

Yes. Immunity to a type of damage doesn't impact other effects of a spell that also causes that type of damage. The other effects of Staggering Smite are to impose disadvantage on attack rolls and ability checks, and prohibit taking reactions. This spell doesn't say it stops any of those things.

Does this protect against the Truth Serum poison?