diff --git a/Libraries/LibWeb/CSS/PseudoClasses.json b/Libraries/LibWeb/CSS/PseudoClasses.json
index 6a187d0f8de..ba69497114c 100644
--- a/Libraries/LibWeb/CSS/PseudoClasses.json
+++ b/Libraries/LibWeb/CSS/PseudoClasses.json
@@ -164,9 +164,6 @@
   "target": {
     "argument": ""
   },
-  "target-within": {
-    "argument": ""
-  },
   "user-invalid": {
     "argument": ""
   },
diff --git a/Libraries/LibWeb/CSS/SelectorEngine.cpp b/Libraries/LibWeb/CSS/SelectorEngine.cpp
index 20233ae0ef1..3a00569e022 100644
--- a/Libraries/LibWeb/CSS/SelectorEngine.cpp
+++ b/Libraries/LibWeb/CSS/SelectorEngine.cpp
@@ -803,12 +803,6 @@ static inline bool matches_pseudo_class(CSS::Selector::SimpleSelector::PseudoCla
     }
     case CSS::PseudoClass::Target:
         return element.is_target();
-    case CSS::PseudoClass::TargetWithin: {
-        auto* target_element = element.document().target_element();
-        if (!target_element)
-            return false;
-        return element.is_inclusive_ancestor_of(*target_element);
-    }
     case CSS::PseudoClass::Dir: {
         // "Values other than ltr and rtl are not invalid, but do not match anything."
         // - https://www.w3.org/TR/selectors-4/#the-dir-pseudo
diff --git a/Libraries/LibWeb/CSS/StyleComputer.cpp b/Libraries/LibWeb/CSS/StyleComputer.cpp
index 06e383caf01..47331d0a3f6 100644
--- a/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -3012,7 +3012,6 @@ void StyleComputer::build_rule_cache()
     m_pseudo_class_rule_cache[to_underlying(PseudoClass::FocusWithin)] = make<RuleCache>();
     m_pseudo_class_rule_cache[to_underlying(PseudoClass::FocusVisible)] = make<RuleCache>();
     m_pseudo_class_rule_cache[to_underlying(PseudoClass::Target)] = make<RuleCache>();
-    m_pseudo_class_rule_cache[to_underlying(PseudoClass::TargetWithin)] = make<RuleCache>();
 
     make_rule_cache_for_cascade_origin(CascadeOrigin::Author, *m_selector_insights);
     make_rule_cache_for_cascade_origin(CascadeOrigin::User, *m_selector_insights);
diff --git a/Libraries/LibWeb/DOM/Document.cpp b/Libraries/LibWeb/DOM/Document.cpp
index 31603220b5b..ec3e67991f0 100644
--- a/Libraries/LibWeb/DOM/Document.cpp
+++ b/Libraries/LibWeb/DOM/Document.cpp
@@ -2570,15 +2570,12 @@ void Document::set_target_element(GC::Ptr<Element> element)
     if (old_target_node_root != new_target_node_root) {
         if (old_target_node_root) {
             invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::Target, m_target_element, *old_target_node_root, element);
-            invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::TargetWithin, m_target_element, *old_target_node_root, element);
         }
         if (new_target_node_root) {
             invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::Target, m_target_element, *new_target_node_root, element);
-            invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::TargetWithin, m_target_element, *new_target_node_root, element);
         }
     } else {
         invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::Target, m_target_element, *common_ancestor, element);
-        invalidate_style_for_elements_affected_by_pseudo_class_change(CSS::PseudoClass::TargetWithin, m_target_element, *common_ancestor, element);
     }
 
     m_target_element = element;