Opportunity Attacks in D&D 5e (Explained): When They Trigger and How to Avoid Them

1 April 2026

Opportunity attacks are the etiquette of melee range written into rules: if you turn your shoulder and leave without disengaging, the monster gets a swing on your way out, one melee attack, usually, powered by the defender’s reaction. New players take lethal hits they didn’t “earn” because movement looked harmless on a grid.

Read this once, then teach it to your table, reactions are explained more broadly in how reactions work, and the whole combat loop in how combat works.

What provokes (the rule you’ll cite)

You can make an opportunity attack when a hostile creature you can see moves out of your reach, using movement, an action, or a reaction that actually moves them.

You use your reaction for the attack. The attack is one melee weapon attack, not a whole Attack action unless a feature says otherwise.

What usually doesn’t provoke

These are the exits players forget are safe by default:

• Teleportation out of reach.
• Forced movement that doesn’t use the creature’s movement, action, or reaction (for example, thunderwave-shoved, spirited away by an effect. The rule’s heart is: you didn’t choose to move yourself with your movement).
• Disengage. If a creature Disengages, its movement doesn’t provoke opportunity attacks for the rest of that turn.
• Movement that never leaves reach, circling inside a threatened band doesn’t cross the boundary that triggers an opportunity attack.

If your build relies on repositioning allies, read the spell/feature, good team tools often move creatures without making them spend movement to leave reach.

How you leave without paying the tab

• Disengage action when you need out now and can’t eat a swing.
• Stay inside the threat if you can end the threat this turn (sometimes damage beats retreat).
• Spells and abilities that move you without using your movement in the provoking way, misty step classics, skip the swing.

Tactical pair-read: Dodge, Dash, Disengage.

Reach, size, and grid psychology

Opportunity attacks care about reach, not vibes. A polearm threatens farther; some monsters reach 10. Mentally trace the hex/square edge where “out of reach” happens before you move.

Conditions that change whether you can leave

If your speed is 0 (grappled usually), you may not move out at all until you fix the condition, different problem than an opportunity attack.

Useful reads:

• Prone, standing costs movement.
• Grappled, speed math.
• Restrained, disadvantage + speed issues.

One-paragraph version

Leaving reach with visible hostile movement provokes Disengage, teleport, or forced movement rules say otherwise. It costs the reaction of the defender. Learn that sentence and you’ll stop feeding free damage to monsters.

Team tool: Help sets up a kill; Disengage saves the wizard, different jobs, same fight.