Can you sneak attack on an attack of Opportunity?

[Rogue problem]

If an opponent moves through the space between two players so that they are flanking would the rogues attack of opportunity be a sneak attack. What if the other player had no Attack of opportunity left to threaten the passing enemy?

Same question also for the Rogue's opportunist special ability.

 

[frankthedm]

Sneak attack can be applied on an AoO. The victim has to be leaving the square in which they are flanked though. Few should be that stupid.

Threatening does not turn off when you run out of AoOs.

 

[Patlin]

Yep, on any attack that meets all of the requirements, sneak attacks apply. Flanking an eligible creature gets you a sneak attack, even on an AOO.

Whether your buddy has an AOO available is immaterial.