diff --git a/Meta/CMake/libweb_generators.cmake b/Meta/CMake/libweb_generators.cmake
index 4d28dea77d..2c3ac62cbd 100644
--- a/Meta/CMake/libweb_generators.cmake
+++ b/Meta/CMake/libweb_generators.cmake
@@ -45,6 +45,15 @@ function (generate_css_implementation)
         arguments -j "${LIBWEB_INPUT_FOLDER}/CSS/Properties.json"
     )
 
+    invoke_generator(
+        "PseudoClass.cpp"
+        Lagom::GenerateCSSPseudoClass
+        "${LIBWEB_INPUT_FOLDER}/CSS/PseudoClasses.json"
+        "CSS/PseudoClass.h"
+        "CSS/PseudoClass.cpp"
+        arguments -j "${LIBWEB_INPUT_FOLDER}/CSS/PseudoClasses.json"
+    )
+
     invoke_generator(
         "TransformFunctions.cpp"
         Lagom::GenerateCSSTransformFunctions
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/CMakeLists.txt b/Meta/Lagom/Tools/CodeGenerators/LibWeb/CMakeLists.txt
index 36bf2da12b..7c50a50591 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/CMakeLists.txt
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/CMakeLists.txt
@@ -5,6 +5,7 @@ lagom_tool(GenerateCSSEnums                 SOURCES GenerateCSSEnums.cpp LIBS Li
 lagom_tool(GenerateCSSMathFunctions         SOURCES GenerateCSSMathFunctions.cpp LIBS LibMain)
 lagom_tool(GenerateCSSMediaFeatureID        SOURCES GenerateCSSMediaFeatureID.cpp LIBS LibMain)
 lagom_tool(GenerateCSSPropertyID            SOURCES GenerateCSSPropertyID.cpp LIBS LibMain)
+lagom_tool(GenerateCSSPseudoClass           SOURCES GenerateCSSPseudoClass.cpp LIBS LibMain)
 lagom_tool(GenerateCSSTransformFunctions    SOURCES GenerateCSSTransformFunctions.cpp LIBS LibMain)
 lagom_tool(GenerateCSSValueID               SOURCES GenerateCSSValueID.cpp LIBS LibMain)
 lagom_tool(GenerateWindowOrWorkerInterfaces SOURCES GenerateWindowOrWorkerInterfaces.cpp LIBS LibMain LibIDL)
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSPseudoClass.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSPseudoClass.cpp
new file mode 100644
index 0000000000..88808dfac3
--- /dev/null
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSPseudoClass.cpp
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 2022-2023, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "GeneratorUtil.h"
+#include <AK/SourceGenerator.h>
+#include <LibCore/ArgsParser.h>
+#include <LibMain/Main.h>
+
+ErrorOr<void> generate_header_file(JsonObject& pseudo_classes_data, Core::File& file);
+ErrorOr<void> generate_implementation_file(JsonObject& pseudo_classes_data, Core::File& file);
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    StringView generated_header_path;
+    StringView generated_implementation_path;
+    StringView identifiers_json_path;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(generated_header_path, "Path to the PseudoClasses header file to generate", "generated-header-path", 'h', "generated-header-path");
+    args_parser.add_option(generated_implementation_path, "Path to the PseudoClasses implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
+    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
+    args_parser.parse(arguments);
+
+    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
+    VERIFY(json.is_object());
+    auto data = json.as_object();
+
+    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
+    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
+
+    TRY(generate_header_file(data, *generated_header_file));
+    TRY(generate_implementation_file(data, *generated_implementation_file));
+
+    return 0;
+}
+
+ErrorOr<void> generate_header_file(JsonObject& pseudo_classes_data, Core::File& file)
+{
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+
+    TRY(generator.try_append(R"~~~(
+#pragma once
+
+#include <AK/Optional.h>
+#include <AK/StringView.h>
+
+namespace Web::CSS {
+
+enum class PseudoClass {
+)~~~"));
+
+    TRY(pseudo_classes_data.try_for_each_member([&](auto& name, auto&) -> ErrorOr<void> {
+        auto member_generator = TRY(generator.fork());
+        TRY(member_generator.set("name:titlecase", TRY(title_casify(name))));
+
+        TRY(member_generator.try_appendln("    @name:titlecase@,"));
+        return {};
+    }));
+    TRY(generator.try_append(R"~~~(
+};
+
+Optional<PseudoClass> pseudo_class_from_string(StringView);
+StringView pseudo_class_name(PseudoClass);
+
+struct PseudoClassMetadata {
+    enum class ParameterType {
+        None,
+        ANPlusB,
+        ANPlusBOf,
+        ForgivingSelectorList,
+        LanguageRanges,
+        SelectorList,
+    } parameter_type;
+    bool is_valid_as_function;
+    bool is_valid_as_identifier;
+};
+PseudoClassMetadata pseudo_class_metadata(PseudoClass);
+
+}
+)~~~"));
+
+    TRY(file.write_until_depleted(generator.as_string_view().bytes()));
+    return {};
+}
+
+ErrorOr<void> generate_implementation_file(JsonObject& pseudo_classes_data, Core::File& file)
+{
+    StringBuilder builder;
+    SourceGenerator generator { builder };
+
+    TRY(generator.try_append(R"~~~(
+#include <LibWeb/CSS/PseudoClass.h>
+
+namespace Web::CSS {
+
+Optional<PseudoClass> pseudo_class_from_string(StringView string)
+{
+)~~~"));
+
+    TRY(pseudo_classes_data.try_for_each_member([&](auto& name, auto&) -> ErrorOr<void> {
+        auto member_generator = TRY(generator.fork());
+        TRY(member_generator.set("name", TRY(String::from_deprecated_string(name))));
+        TRY(member_generator.set("name:titlecase", TRY(title_casify(name))));
+
+        TRY(member_generator.try_append(R"~~~(
+    if (string.equals_ignoring_ascii_case("@name@"sv))
+        return PseudoClass::@name:titlecase@;
+)~~~"));
+        return {};
+    }));
+
+    TRY(generator.try_append(R"~~~(
+
+    return {};
+}
+
+StringView pseudo_class_name(PseudoClass pseudo_class)
+{
+    switch (pseudo_class) {
+)~~~"));
+
+    TRY(pseudo_classes_data.try_for_each_member([&](auto& name, auto&) -> ErrorOr<void> {
+        auto member_generator = TRY(generator.fork());
+        TRY(member_generator.set("name", TRY(String::from_deprecated_string(name))));
+        TRY(member_generator.set("name:titlecase", TRY(title_casify(name))));
+
+        TRY(member_generator.try_append(R"~~~(
+    case PseudoClass::@name:titlecase@:
+        return "@name@"sv;
+)~~~"));
+        return {};
+    }));
+
+    TRY(generator.try_append(R"~~~(
+    }
+    VERIFY_NOT_REACHED();
+}
+
+PseudoClassMetadata pseudo_class_metadata(PseudoClass pseudo_class)
+{
+    switch (pseudo_class) {
+)~~~"));
+
+    TRY(pseudo_classes_data.try_for_each_member([&](auto& name, JsonValue const& value) -> ErrorOr<void> {
+        auto member_generator = TRY(generator.fork());
+        auto& pseudo_class = value.as_object();
+        auto argument_string = pseudo_class.get_deprecated_string("argument"sv).value();
+
+        bool is_valid_as_identifier = argument_string.is_empty();
+        bool is_valid_as_function = !argument_string.is_empty();
+
+        if (argument_string.ends_with('?')) {
+            is_valid_as_identifier = true;
+            argument_string = argument_string.substring(0, argument_string.length() - 1);
+        }
+
+        String parameter_type = "None"_string;
+        if (is_valid_as_function) {
+            if (argument_string == "<an+b>"sv) {
+                parameter_type = "ANPlusB"_string;
+            } else if (argument_string == "<an+b-of>"sv) {
+                parameter_type = "ANPlusBOf"_string;
+            } else if (argument_string == "<forgiving-selector-list>"sv) {
+                parameter_type = "ForgivingSelectorList"_string;
+            } else if (argument_string == "<language-ranges>"sv) {
+                parameter_type = "LanguageRanges"_string;
+            } else if (argument_string == "<selector-list>"sv) {
+                parameter_type = "SelectorList"_string;
+            } else {
+                warnln("Unrecognized pseudo-class argument type: `{}`", argument_string);
+                VERIFY_NOT_REACHED();
+            }
+        }
+
+        TRY(member_generator.set("name:titlecase", TRY(title_casify(name))));
+        TRY(member_generator.set("parameter_type", parameter_type));
+        TRY(member_generator.set("is_valid_as_function", is_valid_as_function ? "true"_string : "false"_string));
+        TRY(member_generator.set("is_valid_as_identifier", is_valid_as_identifier ? "true"_string : "false"_string));
+
+        TRY(member_generator.try_append(R"~~~(
+    case PseudoClass::@name:titlecase@:
+        return {
+            .parameter_type = PseudoClassMetadata::ParameterType::@parameter_type@,
+            .is_valid_as_function = @is_valid_as_function@,
+            .is_valid_as_identifier = @is_valid_as_identifier@,
+        };
+)~~~"));
+        return {};
+    }));
+
+    TRY(generator.try_append(R"~~~(
+    }
+    VERIFY_NOT_REACHED();
+}
+
+}
+)~~~"));
+
+    TRY(file.write_until_depleted(generator.as_string_view().bytes()));
+    return {};
+}
diff --git a/Meta/gn/secondary/Userland/Libraries/LibWeb/BUILD.gn b/Meta/gn/secondary/Userland/Libraries/LibWeb/BUILD.gn
index a1335d70d7..35ac4b22f5 100644
--- a/Meta/gn/secondary/Userland/Libraries/LibWeb/BUILD.gn
+++ b/Meta/gn/secondary/Userland/Libraries/LibWeb/BUILD.gn
@@ -164,6 +164,23 @@ compiled_action("generate_css_property_id") {
   ]
 }
 
+compiled_action("generate_css_pseudo_class") {
+  tool = "//Meta/Lagom/Tools/CodeGenerators/LibWeb:GenerateCSSPseudoClass"
+  inputs = [ "CSS/PseudoClasses.json" ]
+  outputs = [
+    "$target_gen_dir/CSS/PseudoClass.h",
+    "$target_gen_dir/CSS/PseudoClass.cpp",
+  ]
+  args = [
+    "-h",
+    rebase_path(outputs[0], root_build_dir),
+    "-c",
+    rebase_path(outputs[1], root_build_dir),
+    "-j",
+    rebase_path(inputs[0], root_build_dir),
+  ]
+}
+
 compiled_action("generate_css_transform_functions") {
   tool =
       "//Meta/Lagom/Tools/CodeGenerators/LibWeb:GenerateCSSTransformFunctions"
@@ -228,6 +245,7 @@ source_set("all_generated") {
     ":generate_css_math_functions",
     ":generate_css_media_feature_id",
     ":generate_css_property_id",
+    ":generate_css_pseudo_class",
     ":generate_css_transform_functions",
     ":generate_css_value_id",
     ":generate_default_stylesheet_source",
diff --git a/Userland/Libraries/LibWeb/CMakeLists.txt b/Userland/Libraries/LibWeb/CMakeLists.txt
index f4d0066e4f..70ad8fba51 100644
--- a/Userland/Libraries/LibWeb/CMakeLists.txt
+++ b/Userland/Libraries/LibWeb/CMakeLists.txt
@@ -630,6 +630,7 @@ set(GENERATED_SOURCES
     CSS/MathFunctions.cpp
     CSS/MediaFeatureID.cpp
     CSS/PropertyID.cpp
+    CSS/PseudoClass.cpp
     CSS/QuirksModeStyleSheetSource.cpp
     CSS/TransformFunctions.cpp
     CSS/ValueID.cpp
diff --git a/Userland/Libraries/LibWeb/CSS/PseudoClasses.json b/Userland/Libraries/LibWeb/CSS/PseudoClasses.json
new file mode 100644
index 0000000000..942fcd5746
--- /dev/null
+++ b/Userland/Libraries/LibWeb/CSS/PseudoClasses.json
@@ -0,0 +1,116 @@
+{
+  "active": {
+    "argument": ""
+  },
+  "buffering": {
+    "argument": ""
+  },
+  "checked": {
+    "argument": ""
+  },
+  "defined": {
+    "argument": ""
+  },
+  "disabled": {
+    "argument": ""
+  },
+  "empty": {
+    "argument": ""
+  },
+  "enabled": {
+    "argument": ""
+  },
+  "first-child": {
+    "argument": ""
+  },
+  "first-of-type": {
+    "argument": ""
+  },
+  "focus": {
+    "argument": ""
+  },
+  "focus-visible": {
+    "argument": ""
+  },
+  "focus-within": {
+    "argument": ""
+  },
+  "host": {
+    "argument": "<selector-list>?"
+  },
+  "hover": {
+    "argument": ""
+  },
+  "indeterminate": {
+    "argument": ""
+  },
+  "is": {
+    "argument": "<forgiving-selector-list>"
+  },
+  "lang": {
+    "argument": "<language-ranges>"
+  },
+  "last-child": {
+    "argument": ""
+  },
+  "last-of-type": {
+    "argument": ""
+  },
+  "link": {
+    "argument": ""
+  },
+  "muted": {
+    "argument": ""
+  },
+  "not": {
+    "argument": "<selector-list>"
+  },
+  "nth-child": {
+    "argument": "<an+b-of>"
+  },
+  "nth-last-child": {
+    "argument": "<an+b-of>"
+  },
+  "nth-last-of-type": {
+    "argument": "<an+b>"
+  },
+  "nth-of-type": {
+    "argument": "<an+b>"
+  },
+  "only-child": {
+    "argument": ""
+  },
+  "only-of-type": {
+    "argument": ""
+  },
+  "paused": {
+    "argument": ""
+  },
+  "playing": {
+    "argument": ""
+  },
+  "root": {
+    "argument": ""
+  },
+  "scope": {
+    "argument": ""
+  },
+  "seeking": {
+    "argument": ""
+  },
+  "stalled": {
+    "argument": ""
+  },
+  "target": {
+    "argument": ""
+  },
+  "visited": {
+    "argument": ""
+  },
+  "volume-locked": {
+    "argument": ""
+  },
+  "where": {
+    "argument": "<forgiving-selector-list>"
+  }
+}