In what situations would a target be denied a Dex bonus to AC?

Question

I have an encounter coming up where my PCs will face a high level rogue. Naturally, I'd like to use his sneak attack ability, but I've never played a rogue before so I'm light on experience.

From the rules, I see that sneak attack damage is applied when:

1. The rogue's target would be denied a Dexterity bonus to AC (whether the target actually has a Dexterity bonus or not)
2. The rogue flanks her target.

For #1, is there a list of non-magical situations/conditions where a target would be denied a Dex bonus to AC? Is there a page in the PHB that includes this, that I'm just not finding?

Answer 1

I did some more research online and some situations/conditions, where a target is denied its dex bonus to AC, are:

1. Blinded
2. Cowering
3. Flat-Footed (target hasn't yet acted in combat)
4. Attacker is Invisible
5. Stunned
6. Paralyzed
7. Helpless
8. Pinned via Grapple
9. Acrobatics to Cross Narrow Surfaces/Uneven Ground
10. Climbing
11. Running
12. Squeezing
13. Social situations preventing awareness of the attack
14. Successfully Feinted against
15. Overloaded from encumbrance
16. "off balance" in the water

See also the Combat Modifiers table.

Note that flanking a target allows a rogue to use Sneak Attack and gives a +2 attack bonus, but does not actually deny a target's dex bonus to AC.

Are the others I've missed?

Answer 2

Combat Modifiers in the Combat chapter outlines the main conditions that deny Dexterity bonus to AC:

• Attacker is invisible (attacker gains +2 to attack)
• Target is blinded (target suffers -2 to AC)
• Target is cowering, such as from a fear spell (-2 to AC)
• Target is flat-footed because he has not taken his turn yet in this combat
• D&D 3.5 only, not Pathfinder: Target is grappling someone other than the attacker
• Target is helpless, e.g.: unconscious, sleeping, paralyzed, bound (-4 to AC against melee, and Dex modifier counts as -5)
• Target is pinned (-4 to AC against melee)
• Target is stunned (-2 to AC)

Other circumstances in which a creature loses its Dexterity bonus to AC:

• Running, unless you have the Run feat
• Squeezing through a gap less than half your space's width
• Off-balance when fighting underwater, usually due to a failed Swim check
• Using Acrobatics to cross narrow surfaces or uneven ground
• Climbing
• Attacker makes a successful feint
• Attacker is using certain feats, such as Disengaging Shot or False Opening
• Attacker has certain class abilities, such as the Magus ability prescient attack

You don't lose Dexterity to AC just for being prone or casting a spell. In D&D 3.5, your target is denied Dexterity to AC if grappled by someone other than yourself, but this no longer occurs in Pathfinder unless the target is also pinned.