diff --git a/components/style/values/specified/image.rs b/components/style/values/specified/image.rs
index 844e50cbf79..9bf565ac635 100644
--- a/components/style/values/specified/image.rs
+++ b/components/style/values/specified/image.rs
@@ -227,9 +227,21 @@ impl Parse for Gradient {
 
         let (shape, repeating, mut compat_mode) = match result {
             Some(result) => result,
-            None => return Err(input.new_custom_error(StyleParseErrorKind::UnexpectedFunction(func.clone()))),
+            None => return Err(input.new_custom_error(StyleParseErrorKind::UnexpectedFunction(func))),
         };
 
+        #[cfg(feature = "gecko")]
+        {
+            use gecko_bindings::structs;
+            if compat_mode == CompatMode::Moz &&
+                !unsafe { structs::StaticPrefs_sVarCache_layout_css_prefixes_gradients }
+            {
+                return Err(input.new_custom_error(
+                    StyleParseErrorKind::UnexpectedFunction(func)
+                ));
+            }
+        }
+
         let (kind, items) = input.parse_nested_block(|i| {
             let shape = match shape {
                 Shape::Linear => GradientKind::parse_linear(context, i, &mut compat_mode)?,