diff --git a/CHANGELOG.md b/CHANGELOG.md
index 71c32a44..d2cf7fa6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## (???) Not Released Yet
+
+### Minor changes and fixes
+
+* Fix #660: don't send headers twice on emoji router errors.
+
 ## 12.0.3
 
 ### Minor changes and fixes
diff --git a/server/lib/routers/emojis.ts b/server/lib/routers/emojis.ts
index 182eab0f..454f8608 100644
--- a/server/lib/routers/emojis.ts
+++ b/server/lib/routers/emojis.ts
@@ -78,7 +78,9 @@ export async function initEmojisRouter (
           },
           (err) => {
             if (err) {
-              res.sendStatus(404)
+              if (!res.headersSent) {
+                res.sendStatus(404)
+              }
             }
           }
         )