# Reaction *Source: Player's Handbook (2024) p. 372. Available in the <span title='Systems Reference Document (5.2)'>SRD</span> and the Free Rules (2024)* A Reaction is a special action taken in response to a trigger defined in the Reaction's description. You can take a Reaction on another creature's turn, and if you take it on your turn, you can do so even if you also take an action, a [Bonus Action](Mechanics/CLI/rules/variant-rules/bonus-action-xphb.md), or both. Once you take a Reaction, you can't take another one until the start of your next turn. The [Opportunity Attack](Mechanics/CLI/rules/actions.md#Opportunity%20Attack) is a Reaction available to all creatures.