diff --git a/layout/style/nsCSSPropAliasList.h b/layout/style/nsCSSPropAliasList.h
index 782194eb7f05..6c37268f1bc3 100644
--- a/layout/style/nsCSSPropAliasList.h
+++ b/layout/style/nsCSSPropAliasList.h
@@ -118,7 +118,7 @@ CSS_PROP_ALIAS(-moz-animation-timing-function,
 CSS_PROP_ALIAS(-moz-box-sizing,
                box_sizing,
                MozBoxSizing,
-               "")
+               "layout.css.prefixes.box-sizing")
 CSS_PROP_ALIAS(font-feature-settings,
                font_feature_settings,
                FontFeatureSettings,
diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index abcebc5f32f7..6e2225c8c1bb 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -1785,6 +1785,7 @@ pref("layout.css.prefixes.border-image", true);
 pref("layout.css.prefixes.transforms", true);
 pref("layout.css.prefixes.transitions", true);
 pref("layout.css.prefixes.animations", true);
+pref("layout.css.prefixes.box-sizing", true);
 
 // Is support for the :scope selector enabled?
 #ifdef RELEASE_BUILD