Struggling to get how Ready and Reaction interact. If a player says I want to take the Ready action and wait for an orc to pop his head out and then shoot him that is a reaction and also his full action. But are there special reactions that don't require announcing of the trigger like Uncanny Dodge or Opportunity Attacks but which also allow the PC to take a full action?

Could a Rogue attack (action), disengage/dash/etc. (bonus action) and Uncanny Dodge (reaction) on a single turn?


4 Answers 4


Reactions are actions that you take out of turn (or possibly on your turn) that happen in response to something else. A reaction can never occur without a trigger.

A Ready action is a special type of action that uses your action to prepare for a triggering event, and when that event occurs you use your reaction to perform whatever you had readied.

To step back a moment, you have four "action types" you can make:

  • Action
  • Bonus Action
  • Reaction
  • Movement

On each round, you get one of each of these things. On your turn, you can use an action, a bonus action (if some class feature, feat, spell, or some other thing grants you one), and you can move up to your movement speed (if you use the Dash action you also move as your action). You also get a free "interact with an object" (does not include magic item activation/use). Whenever a triggering event for a reaction occurs, you can also use your reaction. Anything that requires a reaction will tell you what the triggering event is, except in the case of a Ready action, where you actually determine the triggering event yourself.

A Ready action uses an action on your turn to, as I mentioned previously, prepare for some triggered event which then uses your reaction to perform. So when you Ready you might say, "I Ready my firebolt cantrip to cast at the first orc that steps through that doorway."

This uses your action for that turn. Then, when the triggering event occurs, you can do as you have described, using your reaction to complete the Ready action, OR you have the option to move up to your movement you instead (irrespective of if you moved or not on your turn).

So, in essence, a Ready action uses both the action and reaction granted for that combat round, and once your Ready action has triggered you cannot act again until your next turn.

One other note for readying spells -- when you Ready a spell you actually cast the spell using your regular turn action, and "hold" it until the triggering event occurs. Note that this usage requires concentration. You can cast the spell as long as you continue concentrating on holding it.

It is important to note also that because you only get one reaction per combat round that if you have taken an Opportunity Attack or cast a spell with a casting time of reaction (such as Shield) then you cannot use your reaction to complete your ready action (but you might still have movement remaining). On the other hand, if you have taken the Ready action and your trigger has occurred and thus you've used your reaction for that round, then you cannot cast a reaction spell or take any Opportunity Attacks (barring any special abilities/feats that might grant additional OA's).

Your rogue can absolutely attack (action), disengage/dash/etc. (bonus action from Rogue Cunning Action) and Uncanny Dodge (reaction) on a single turn, but he can only Uncanny Dodge in reaction to a triggering event (outlined in the rules for Uncanny Dodge).

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    \$\begingroup\$ Thanks. A Ready action creates the trigger while a Reaction is based on a pre-existing trigger. That clarified my thinking. \$\endgroup\$
    – LordAo
    May 9, 2016 at 18:33
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    \$\begingroup\$ The readied action takes your reaction to perform. That is: You use your action ready to attack any enemy that comes within reach. An enemy comes within reach, you use your reaction to attack. You no longer have your reaction left to uncanny dodge. On the other hand, if you've readied the attack action, but before it gets triggered something attacks you -- you can use the uncanny dodge -- which would spend your reaction so you can no longer do the attack. \$\endgroup\$ May 9, 2016 at 19:13
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    \$\begingroup\$ I'd like to see "Free Object Interaction" added to the list of four action types, since it's budgeted one-per-turn exactly the same way as the rest of them. I kind of wish the designers had given it a more precise name (like 3e's "swift action" or 4e's "minor action"). \$\endgroup\$
    – Sebkha
    May 10, 2016 at 3:12
  • \$\begingroup\$ @Sebkha I considered it, but it's not really the same as the other "per round" actions, because interact with an object is an action, it's only granted for free the first time in a round on your turn. If you want to interact with another object after that, it's an action, and all of that is really outside the scope of the question/answer. \$\endgroup\$ May 10, 2016 at 3:16
  • \$\begingroup\$ @LegendaryDude Could similarly argue that movement is only granted for free the first time in a round, and if you want to move further after that, it's a Dash action. Downplaying object interactions seems to be RAI, though. \$\endgroup\$
    – Sebkha
    May 10, 2016 at 3:23

Yes, a rogue could Attack and Cunning Action, however uncanny dodge is not used on your turn but rather, the turn of the attacking enemy. You don't require the ready action to do this as a reaction because it is a reaction to being harmed. It's unconscious. You don't think about, it just happens. If you flinch if something rushes towards you, that is you reacting to defend yourself from danger. Now, picking up a bow, drawing it back and firing is not an automatic reaction to damage. If you prepare yourself (Ready action) you could do it as a reaction, but you must use up your action preparing to defend.

  • \$\begingroup\$ Uncanny dodge can be used on your own turn as a reaction to someone else's reaction, i.e. receiving an opportunity attack. \$\endgroup\$ Nov 6, 2017 at 3:34


Generally characters get one action, one bonus action, and one reaction. The ready action is kind of an outlier here as it uses your action to prepare a reaction. You could use your reaction for Uncanny Dodge, an Opportunity Attack, or any other ability that uses a reaction.

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    \$\begingroup\$ @LegendaryDude Hmmm, indeed it was. \$\endgroup\$
    – Kyle W
    May 9, 2016 at 19:11

To sum up for anyone having difficulty digesting these replies: if you ready an action and have not used it and decide to make an opportunity attacks against an enemy you lose your readied action. Imagine a ranger with a bow drawn on a door waiting for an enemy and suddenly an enemy sneaks behind you and you notice and decide to attack the present danger, you have quit watching the doorway to opportunity attack that notsoquiet kobold. This makes intuitive sense, and the ruling on it coincides with what happens in real combat.

Conversely, if you stay focused on the doorway, you let the kobold pass. No opportunity attack.


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