diff --git a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
index 5146580e19..e121b3f1b9 100644
--- a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
+++ b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
  * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Alexander Narsudinov <a.narsudinov@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -132,6 +133,33 @@ Attr const* NamedNodeMap::get_attribute(StringView qualified_name, size_t* item_
     return nullptr;
 }
 
+// https://dom.spec.whatwg.org/#concept-element-attributes-get-by-namespace
+Attr* NamedNodeMap::get_attribute_ns(StringView namespace_, StringView local_name, size_t* item_index)
+{
+    return const_cast<Attr*>(const_cast<NamedNodeMap const*>(this)->get_attribute_ns(namespace_, local_name, item_index));
+}
+
+// https://dom.spec.whatwg.org/#concept-element-attributes-get-by-namespace
+Attr const* NamedNodeMap::get_attribute_ns(StringView namespace_, StringView local_name, size_t* item_index) const
+{
+    if (item_index)
+        *item_index = 0;
+
+    // 1. If namespace is the empty string, then set it to null.
+    if (namespace_.is_empty())
+        namespace_ = {};
+
+    // 2. Return the attribute in element’s attribute list whose namespace is namespace and local name is localName, if any; otherwise null.
+    for (auto const& attribute : m_attributes) {
+        if (attribute->namespace_uri() == namespace_ && attribute->local_name() == local_name)
+            return attribute.ptr();
+        if (item_index)
+            ++(*item_index);
+    }
+
+    return nullptr;
+}
+
 // https://dom.spec.whatwg.org/#concept-element-attributes-set
 WebIDL::ExceptionOr<Attr const*> NamedNodeMap::set_attribute(Attr& attribute)
 {
diff --git a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
index bc2f2a1f84..b79e65a12f 100644
--- a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
+++ b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
  * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Alexander Narsudinov <a.narsudinov@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -40,7 +41,9 @@ public:
 
     // Methods defined by the spec for internal use:
     Attr* get_attribute(StringView qualified_name, size_t* item_index = nullptr);
+    Attr* get_attribute_ns(StringView namespace_, StringView local_name, size_t* item_index = nullptr);
     Attr const* get_attribute(StringView qualified_name, size_t* item_index = nullptr) const;
+    Attr const* get_attribute_ns(StringView namespace_, StringView local_name, size_t* item_index = nullptr) const;
     WebIDL::ExceptionOr<Attr const*> set_attribute(Attr& attribute);
     void replace_attribute(Attr& old_attribute, Attr& new_attribute, size_t old_attribute_index);
     void append_attribute(Attr& attribute);