An **Opportunity Attack** is a quick strike you can make when an enemy **carelessly moves away from you**.
It represents taking advantage of an opening.
#### The Core Rule (Read This First)
> **If a creature leaves your reach without being careful, you can hit them.**
#### When Does an Opportunity Attack Happen?
An Opportunity Attack happens when:
- A creature **you can see**
- **Leaves your melee reach**
- **Using movement**
When this happens, you may use your **Reaction** to attack.
#### When Opportunity Attacks Do NOT Happen
No Opportunity Attack if the creature:
- Uses the **Disengage** action
- Is moved by **forced movement** (pushed, pulled, thrown)
- Teleports
- Is already out of your reach
#### What You Can Do
When you make an Opportunity Attack:
- You make **one melee attack**
- No extra attacks
- No bonus actions
Most creatures use a weapon or unarmed strike.
#### Spells & Opportunity Attacks
Normally:
- You **cannot** cast a spell as an Opportunity Attack
Unless:
- The spell specifically says it can be cast as a reaction
(e.g. _Booming Blade_ with War Caster)
#### Reach Matters
- Most creatures have **5 ft reach**
- Creatures with reach weapons threaten a larger area
- Leaving any threatened space can trigger the attack
Example:
- A creature moves from 10 ft to 15 ft away from a glaive user → triggers
#### Opportunity Attacks & Reactions
- You get **one Reaction per round**
- If you’ve already used your reaction, you can’t make one
- Reaction refreshes at the start of your next turn
#### DM Rule of Thumb
> **Opportunity Attacks punish careless movement, not smart tactics.**
#### Summary
> **Move away without disengaging, and you might get hit.**
#### 🧠 Quick Reference
|Situation|Opportunity Attack?|
|---|---|
|Walk away|✅|
|Disengage|❌|
|Teleport|❌|
|Pushed / Pulled|❌|
|Move within reach|❌|