diff --git a/css/properties/font-variant-emoji.json b/css/properties/font-variant-emoji.json
index 6e57cf1b71f9d..01b69fecb56b2 100644
--- a/css/properties/font-variant-emoji.json
+++ b/css/properties/font-variant-emoji.json
@@ -12,7 +12,14 @@
             "chrome_android": "mirror",
             "edge": "mirror",
             "firefox": {
-              "version_added": "108"
+              "version_added": "108",
+              "flags": [
+                {
+                  "name": "layout.css.font-variant-emoji.enabled",
+                  "type": "preference",
+                  "value_to_set": "true"
+                }
+              ]
             },
             "firefox_android": "mirror",
             "ie": {