diff --git a/Userland/Libraries/LibWeb/CSS/Identifiers.json b/Userland/Libraries/LibWeb/CSS/Identifiers.json
index 2f66bf8167..1bbb27730d 100644
--- a/Userland/Libraries/LibWeb/CSS/Identifiers.json
+++ b/Userland/Libraries/LibWeb/CSS/Identifiers.json
@@ -160,6 +160,8 @@
   "text",
   "underline",
   "uppercase",
+  "upper-alpha",
+  "upper-latin",
   "visible",
   "vertical-text",
   "wait",
diff --git a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
index 9860bb1254..01bf6b4d68 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
@@ -582,6 +582,10 @@ Optional<CSS::ListStyleType> StyleProperties::list_style_type() const
         return CSS::ListStyleType::LowerAlpha;
     case CSS::ValueID::LowerLatin:
         return CSS::ListStyleType::LowerLatin;
+    case CSS::ValueID::UpperAlpha:
+        return CSS::ListStyleType::UpperAlpha;
+    case CSS::ValueID::UpperLatin:
+        return CSS::ListStyleType::UpperLatin;
     default:
         return {};
     }
diff --git a/Userland/Libraries/LibWeb/CSS/StyleValue.h b/Userland/Libraries/LibWeb/CSS/StyleValue.h
index 9a0b472a6d..1a7ca22da2 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleValue.h
+++ b/Userland/Libraries/LibWeb/CSS/StyleValue.h
@@ -162,6 +162,8 @@ enum class ListStyleType {
     DecimalLeadingZero,
     LowerAlpha,
     LowerLatin,
+    UpperAlpha,
+    UpperLatin,
 };
 
 enum class Overflow : u8 {
diff --git a/Userland/Libraries/LibWeb/Layout/ListItemMarkerBox.cpp b/Userland/Libraries/LibWeb/Layout/ListItemMarkerBox.cpp
index dc201e4712..1d91d37d84 100644
--- a/Userland/Libraries/LibWeb/Layout/ListItemMarkerBox.cpp
+++ b/Userland/Libraries/LibWeb/Layout/ListItemMarkerBox.cpp
@@ -12,6 +12,7 @@
 namespace Web::Layout {
 
 constexpr auto lower_alpha = "abcdefghijklmnopqrstuvwxyz";
+constexpr auto upper_alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
 ListItemMarkerBox::ListItemMarkerBox(DOM::Document& document, CSS::ListStyleType style_type, size_t index)
     : Box(document, nullptr, CSS::StyleProperties::create())
@@ -81,6 +82,10 @@ void ListItemMarkerBox::paint(PaintContext& context, PaintPhase phase)
     case CSS::ListStyleType::LowerLatin:
         context.painter().draw_text(enclosing, number_to_alphabet(m_index, lower_alpha), Gfx::TextAlignment::Center);
         break;
+    case CSS::ListStyleType::UpperAlpha:
+    case CSS::ListStyleType::UpperLatin:
+        context.painter().draw_text(enclosing, number_to_alphabet(m_index, upper_alpha), Gfx::TextAlignment::Center);
+        break;
     case CSS::ListStyleType::None:
         return;