diff --git a/components/script/dom/htmlcollection.rs b/components/script/dom/htmlcollection.rs
index d5198b94986..f1eb1fdd706 100644
--- a/components/script/dom/htmlcollection.rs
+++ b/components/script/dom/htmlcollection.rs
@@ -252,11 +252,17 @@ impl HTMLCollection {
                 let case_sensitivity = document_from_node(elem)
                     .quirks_mode()
                     .classes_and_ids_case_sensitivity();
+
                 self.classes
                     .iter()
                     .all(|class| elem.has_class(class, case_sensitivity))
             }
         }
+
+        if classes.is_empty() {
+            return HTMLCollection::always_empty(window, root);
+        }
+
         let filter = ClassNameFilter { classes: classes };
         HTMLCollection::create(window, root, Box::new(filter))
     }
diff --git a/tests/wpt/metadata/dom/nodes/getElementsByClassName-empty-set.html.ini b/tests/wpt/metadata/dom/nodes/getElementsByClassName-empty-set.html.ini
deleted file mode 100644
index 88cb5872361..00000000000
--- a/tests/wpt/metadata/dom/nodes/getElementsByClassName-empty-set.html.ini
+++ /dev/null
@@ -1,10 +0,0 @@
-[getElementsByClassName-empty-set.html]
-  [Passing a space to getElementsByClassName should return an empty HTMLCollection]
-    expected: FAIL
-
-  [Passing three spaces to getElementsByClassName should return an empty HTMLCollection]
-    expected: FAIL
-
-  [Passing an empty string to getElementsByClassName should return an empty HTMLCollection]
-    expected: FAIL
-