Dun Dun is an all-caps typed reaction used online after a mildly dramatic statement, often written as "DUN DUN" or "DUN DUN DUN".

Where did Dun Dun come from?

It spread on 4chan's /b/ board in late May 2010 during the same week Law & Order aired its 20th-season finale on NBC.

What does Dun Dun mean?

The phrase signals a mock-serious "gotcha" reaction, echoing the dramatic gavel sting that punctuates scenes on Law & Order.

How do you use Dun Dun?

Type it in all caps at the end of a message, usually right after a small twist, a petty grievance, or an overdramatic statement, to give the moment a courtroom-drama beat.

Is Dun Dun still popular?

It broke out in May 2010 around Law & Order's 20th-season finale week and is now looked back on as classic 4chan-era slang rather than a currently trending reply.

Dun Dun

2010catchphraseclassic

Published August 19, 2026

"Dun Dun" is the typed version of the two-note gavel sting from NBC's Law & Order, used online as shorthand for a mock-dramatic reply. The phrase broke out on 4chan's /b/ board in May 2010 after moderators changed the site's post-confirmation screen to read "DUN DUN Post Successful," and users started ending posts with it.

catchphrase memes 4chan memes tv show memes sound effect memes reaction memes

Overview

"Dun Dun" is the all-caps text stand-in for the two-note gavel sting heard between scenes on NBC's Law & Order3. People type it after a mildly dramatic statement to give the moment a mock-courtroom beat, usually as "DUN DUN" or stretched to "DUN DUN DUN" for extra weight4.

Law & Order ran for 20 seasons on NBC before its finale in May 20102. The typed version works as a reaction shorthand along the same lines as "record scratch" or "gasp," hitting hardest after a small revelation or an awkward admission4.

Gallery

Origin & Background

Platform

4chan

Date

2010

"DUN DUN" as internet slang came out of 4chan's /b/ board in late May 2010. On May 24, moderators quietly swapped the site's post-confirmation screen with a "DUN DUN Post Successful" graphic, and users on /b/ started tacking "DUN DUN" onto the end of their own posts3.

That same day, NBC aired the 20th-season finale of Law & Order, titled "Rubber Room," in which detectives investigated a heavily armed anonymous blogger who called himself "Moot"1. The alias overlapped with the handle used by 4chan founder Christopher Poole, and the collision between the show's plot and the site's culture gave the joke extra fuel on /b/ that week1.

How It Spread

The "DUN DUN Post Successful" splash stayed live on 4chan for two more days before moderators pulled it on May 26, 2010, after users kept ribbing them for leaving the May 24 date untouched at the bottom of the graphic3.

Urban Dictionary entries from that summer logged "DUN DUN" as a reaction to awkward or overdramatic exchanges, with one submitter defining it as a shortening of "so done with this"4. Law & Order itself ended its original run with the May 24 episode after NBC cancelled the show2, and the typed sting kept going as chat shorthand once new episodes stopped airing.

How to Use This Meme

People typically add "DUN DUN" or "DUN DUN DUN" at the end of a message where the tone is mock-serious, often right after a small twist, a petty grievance, or a mildly incriminating detail4. The all-caps form mirrors how loud the Law & Order sting hits on the show, which ran the cue between nearly every scene change across its 20-season run2.