Suppose I am fighting an enemy with the usual 5-foot reach. He is standing next to a wall beside an open doorway. I am in next to him in the room. Without leaving his 5-foot range, I move to the other side of the wall. Does he get an opportunity attack?

--------  -----    to  --------M -----  to--------  -----    
       EM                     E                  E

Assume that the wall is only a foot thick and is halfway in E's square and halfway in mine, so that E(nemy) and M(e) are in adjacent squares in the final diagram. But the enemy cannot reach me through the wall, so have I "left his reach" taking an opportunity attack while in the doorway?

If there was no wall there, I could move to that position without provoking any opportunity attack. Does the wall being there make it easier for the foe to attack me somehow?

Does your analysis change in the 3-dimensional case where the creature potentially leaving reach is an incorporeal creature moving from the square next to an enemy to the square (cube) next to and below the enemy?

  • \$\begingroup\$ One might be tempted to argue that a wall should help the moving creature avoid an OA, perhaps making Disengage cheaper or free. But as per the answers, D&D 5e does not model this level of simulation. \$\endgroup\$ Oct 19, 2020 at 6:18

2 Answers 2


Yes, he gets an OA

You are moving to get away from him, and for sure "being on the other side of the wall" means you are "out of his reach" as most attackers cannot reach through a wall.

The OA doesn't care where you are moving to, the OA condition is set based upon where you are moving from. (Without using the Disengage action).

You can make an opportunity attack when a hostile creature that you can see moves out of your reach.(PHB p. 195)

It further points out that the attack "interrupts the provoking creature's movement," so that you may not get to that bit of cover depending upon the result of the OA. For example, your attempt to get through that door may fail if the attack knocks you out as a result of the OA.

Whether or not the enemy can see you before the attempted move is complete (when the move is begun) determines the "that you can see criterion" not "after the move is completed."(Which is the "behind the wall" condition).

If you want to avoid the OA, use the Disengage action.

Insofar as the incorporeal creature is concerned, that is a separate question.

  • \$\begingroup\$ This is interesting. Does that mean that, say, you have a familiar clinging to your back, and they poke their head over your shoulder to scare your enemy via Help action, then duck back down, does that still provoke OA? \$\endgroup\$
    – Xan3
    Dec 29, 2022 at 19:03
  • \$\begingroup\$ @Xan3 Suggest you ask that as a separate question, link back to this. 😊 \$\endgroup\$ Dec 30, 2022 at 14:48

Yes, he gets an Opportunity Attack

This applies to corporeal, incorporeal, burrowing, etc.

Jeremy Crawford has confirmed this with a pair of tweets:

Tweet 1:

Q: Does an earth elemental trigger an OA when it burrows? It is within 5 ft, but the creature can no longer reach it

A: An opportunity attack occurs right before the target leaves your reach (PH, 195).

Tweet 2:

Q: thanks. yes, the debate here was does it ever leave your reach if it goes into the ground adjacent to you

A: Your melee reach does not extend into the wall or floor.


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