--- a/servo/components/style/properties/longhand/xul.mako.rs
+++ b/servo/components/style/properties/longhand/xul.mako.rs
@@ -26,16 +26,17 @@
 ${helpers.predefined_type("-moz-box-flex", "Number", "0.0", "parse_non_negative",
                           products="gecko", gecko_ffi_name="mBoxFlex",
                           animation_type="none",
                           alias="-webkit-box-flex",
                           spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/box-flex)")}
 
 ${helpers.single_keyword("-moz-box-orient", "horizontal vertical",
                          products="gecko", gecko_ffi_name="mBoxOrient",
+                         extra_gecko_aliases="inline-axis=horizontal block-axis=vertical",
                          gecko_enum_prefix="StyleBoxOrient",
                          animation_type="none",
                          alias="-webkit-box-orient",
                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/box-orient)")}
 
 ${helpers.single_keyword("-moz-box-pack", "start center end justify",
                          products="gecko", gecko_ffi_name="mBoxPack",
                          gecko_enum_prefix="StyleBoxPack",