diff --git a/Libraries/LibWeb/CSS/SelectorEngine.cpp b/Libraries/LibWeb/CSS/SelectorEngine.cpp
index cda81207f42..6b1627e2ed3 100644
--- a/Libraries/LibWeb/CSS/SelectorEngine.cpp
+++ b/Libraries/LibWeb/CSS/SelectorEngine.cpp
@@ -219,8 +219,7 @@ static inline bool matches_attribute(CSS::Selector::SimpleSelector::Attribute co
 
     auto const& attribute_name = attribute.qualified_name.name.name;
 
-    auto const* attr = element.namespace_uri() == Namespace::HTML ? element.attributes()->get_attribute_with_lowercase_qualified_name(attribute_name)
-                                                                  : element.attributes()->get_attribute(attribute_name);
+    auto const* attr = element.attributes()->get_attribute(attribute_name);
 
     if (attribute.match_type == CSS::Selector::SimpleSelector::Attribute::MatchType::HasAttribute) {
         // Early way out in case of an attribute existence selector.
diff --git a/Libraries/LibWeb/DOM/NamedNodeMap.cpp b/Libraries/LibWeb/DOM/NamedNodeMap.cpp
index 11ed46345cf..237538ca554 100644
--- a/Libraries/LibWeb/DOM/NamedNodeMap.cpp
+++ b/Libraries/LibWeb/DOM/NamedNodeMap.cpp
@@ -148,8 +148,7 @@ Attr const* NamedNodeMap::get_attribute(FlyString const& qualified_name, size_t*
         *item_index = 0;
 
     // 1. If element is in the HTML namespace and its node document is an HTML document, then set qualifiedName to qualifiedName in ASCII lowercase.
-    // FIXME: Handle the second condition, assume it is an HTML document for now.
-    bool compare_as_lowercase = associated_element().namespace_uri() == Namespace::HTML;
+    bool compare_as_lowercase = associated_element().namespace_uri() == Namespace::HTML && associated_element().document().is_html_document();
 
     // 2. Return the first attribute in element’s attribute list whose qualified name is qualifiedName; otherwise null.
     for (auto const& attribute : m_attributes) {
@@ -168,19 +167,6 @@ Attr const* NamedNodeMap::get_attribute(FlyString const& qualified_name, size_t*
     return nullptr;
 }
 
-Attr const* NamedNodeMap::get_attribute_with_lowercase_qualified_name(FlyString const& lowercase_qualified_name) const
-{
-    bool compare_as_lowercase = associated_element().namespace_uri() == Namespace::HTML;
-    VERIFY(compare_as_lowercase);
-
-    for (auto const& attribute : m_attributes) {
-        if (attribute->lowercase_name() == lowercase_qualified_name)
-            return attribute;
-    }
-
-    return nullptr;
-}
-
 // https://dom.spec.whatwg.org/#concept-element-attributes-get-by-namespace
 Attr* NamedNodeMap::get_attribute_ns(Optional<FlyString> const& namespace_, FlyString const& local_name, size_t* item_index)
 {
diff --git a/Libraries/LibWeb/DOM/NamedNodeMap.h b/Libraries/LibWeb/DOM/NamedNodeMap.h
index 27052935f52..bf59c3a13db 100644
--- a/Libraries/LibWeb/DOM/NamedNodeMap.h
+++ b/Libraries/LibWeb/DOM/NamedNodeMap.h
@@ -53,8 +53,6 @@ public:
     Attr const* remove_attribute(FlyString const& qualified_name);
     Attr const* remove_attribute_ns(Optional<FlyString> const& namespace_, FlyString const& local_name);
 
-    Attr const* get_attribute_with_lowercase_qualified_name(FlyString const&) const;
-
     WebIDL::ExceptionOr<GC::Ref<Attr>> remove_attribute_node(GC::Ref<Attr>);
 
 private:
diff --git a/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/ParentNode-querySelector-All.txt b/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/ParentNode-querySelector-All.txt
index 9e626d0def9..29487d7992a 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/ParentNode-querySelector-All.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/dom/nodes/ParentNode-querySelector-All.txt
@@ -6,8 +6,8 @@ Rerun
 
 Found 1975 tests
 
-1923 Pass
-52 Fail
+1931 Pass
+44 Fail
 Details
 Result	Test Name	MessagePass	Selectors-API Test Suite: HTML	
 Pass	Document supports querySelector	
@@ -414,8 +414,8 @@ Pass	Document.querySelectorAll: Attribute presence selector, matching align attr
 Pass	Document.querySelector: Attribute presence selector, matching align attribute with value: .attr-presence-div1[align]	
 Pass	Document.querySelectorAll: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
 Pass	Document.querySelector: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
-Fail	Document.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
-Fail	Document.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Document.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Document.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
 Pass	Document.querySelectorAll: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Document.querySelector: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Document.querySelectorAll: Attribute presence selector, not matching attribute with similar name: .attr-presence-div3[align], .attr-presence-div4[align]	
@@ -810,8 +810,8 @@ Pass	Detached Element.querySelectorAll: Attribute presence selector, matching al
 Pass	Detached Element.querySelector: Attribute presence selector, matching align attribute with value: .attr-presence-div1[align]	
 Pass	Detached Element.querySelectorAll: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
 Pass	Detached Element.querySelector: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
-Fail	Detached Element.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
-Fail	Detached Element.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Detached Element.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Detached Element.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
 Pass	Detached Element.querySelectorAll: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Detached Element.querySelector: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Detached Element.querySelectorAll: Attribute presence selector, not matching attribute with similar name: .attr-presence-div3[align], .attr-presence-div4[align]	
@@ -1206,8 +1206,8 @@ Pass	Fragment.querySelectorAll: Attribute presence selector, matching align attr
 Pass	Fragment.querySelector: Attribute presence selector, matching align attribute with value: .attr-presence-div1[align]	
 Pass	Fragment.querySelectorAll: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
 Pass	Fragment.querySelector: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
-Fail	Fragment.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
-Fail	Fragment.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Fragment.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	Fragment.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
 Pass	Fragment.querySelectorAll: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Fragment.querySelector: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	Fragment.querySelectorAll: Attribute presence selector, not matching attribute with similar name: .attr-presence-div3[align], .attr-presence-div4[align]	
@@ -1602,8 +1602,8 @@ Pass	In-document Element.querySelectorAll: Attribute presence selector, matching
 Pass	In-document Element.querySelector: Attribute presence selector, matching align attribute with value: .attr-presence-div1[align]	
 Pass	In-document Element.querySelectorAll: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
 Pass	In-document Element.querySelector: Attribute presence selector, matching align attribute with empty value: .attr-presence-div2[align]	
-Fail	In-document Element.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
-Fail	In-document Element.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	In-document Element.querySelectorAll: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
+Pass	In-document Element.querySelector: Attribute presence selector, matching title attribute, case insensitivity: #attr-presence [*|TiTlE]	
 Pass	In-document Element.querySelectorAll: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	In-document Element.querySelector: Attribute presence selector, matching custom data-* attribute: [data-attr-presence]	
 Pass	In-document Element.querySelectorAll: Attribute presence selector, not matching attribute with similar name: .attr-presence-div3[align], .attr-presence-div4[align]