diff --git a/Userland/Libraries/LibWeb/ARIA/StateAndProperties.cpp b/Userland/Libraries/LibWeb/ARIA/StateAndProperties.cpp
new file mode 100644
index 0000000000..7304d053a7
--- /dev/null
+++ b/Userland/Libraries/LibWeb/ARIA/StateAndProperties.cpp
@@ -0,0 +1,450 @@
+/*
+ * Copyright (c) 2023, Jonah Shafran <jonahshafran@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Variant.h>
+#include <LibWeb/ARIA/StateAndProperties.h>
+
+namespace Web::ARIA {
+
+ErrorOr<String> state_or_property_to_string_value(StateAndProperties state_or_property, AriaData const& aria_data, DefaultValueType default_value)
+{
+    switch (state_or_property) {
+    case StateAndProperties::AriaActiveDescendant: {
+        auto value = aria_data.aria_active_descendant_or_default();
+        return value.has_value() ? String::from_deprecated_string(value.value()) : String::from_utf8(""sv);
+    }
+    case StateAndProperties::AriaAtomic: {
+        bool value;
+        if (default_value.has<bool>())
+            value = aria_data.aria_atomic_or_default(default_value.get<bool>());
+        else
+            value = aria_data.aria_atomic_or_default();
+        return value ? "true"_short_string : "false"_short_string;
+    }
+    case StateAndProperties::AriaAutoComplete: {
+        auto value = aria_data.aria_auto_complete_or_default();
+        switch (value) {
+        case AriaAutocomplete::None:
+            return "none"_short_string;
+        case AriaAutocomplete::List:
+            return "list"_short_string;
+        case AriaAutocomplete::Both:
+            return "both"_short_string;
+        case AriaAutocomplete::Inline:
+            return "inline"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaBusy:
+        return String::from_utf8(aria_data.aria_busy_or_default() ? "true"sv : "false"sv);
+    case StateAndProperties::AriaChecked:
+        return ARIA::tristate_to_string(aria_data.aria_checked_or_default());
+    case StateAndProperties::AriaColCount:
+        return ARIA::optional_integer_to_string(aria_data.aria_col_count_or_default());
+    case StateAndProperties::AriaColIndex:
+        return ARIA::optional_integer_to_string(aria_data.aria_col_index_or_default());
+    case StateAndProperties::AriaColSpan:
+        return ARIA::optional_integer_to_string(aria_data.aria_col_span_or_default());
+    case StateAndProperties::AriaControls:
+        return id_reference_list_to_string(aria_data.aria_controls_or_default());
+    case StateAndProperties::AriaCurrent: {
+        auto value = aria_data.aria_current_or_default();
+        switch (value) {
+        case AriaCurrent::False:
+            return "false"_short_string;
+        case AriaCurrent::True:
+            return "true"_short_string;
+        case AriaCurrent::Date:
+            return "date"_short_string;
+        case AriaCurrent::Location:
+            return "location"_string;
+        case AriaCurrent::Page:
+            return "page"_short_string;
+        case AriaCurrent::Step:
+            return "step"_short_string;
+        case AriaCurrent::Time:
+            return "time"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaDescribedBy:
+        return id_reference_list_to_string(aria_data.aria_described_by_or_default());
+    case StateAndProperties::AriaDetails: {
+        auto value = aria_data.aria_details_or_default();
+        return value.has_value() ? String::from_deprecated_string(value.value()) : String::from_utf8(""sv);
+    }
+    case StateAndProperties::AriaDisabled:
+        return aria_data.aria_disabled_or_default() ? "true"_short_string : "false"_short_string;
+    case StateAndProperties::AriaDropEffect: {
+        StringBuilder builder;
+        auto value = aria_data.aria_drop_effect_or_default();
+        for (auto const drop_effect : value) {
+            StringView to_add;
+            switch (drop_effect) {
+            case AriaDropEffect::Copy:
+                to_add = "copy"sv;
+                break;
+            case AriaDropEffect::Execute:
+                to_add = "execute"sv;
+                break;
+            case AriaDropEffect::Link:
+                to_add = "link"sv;
+                break;
+            case AriaDropEffect::Move:
+                to_add = "move"sv;
+                break;
+            case AriaDropEffect::None:
+                to_add = "none"sv;
+                break;
+            case AriaDropEffect::Popup:
+                to_add = "popup"sv;
+                break;
+            }
+            if (builder.is_empty())
+                builder.append(to_add);
+            else {
+                builder.append(" "sv);
+                builder.append(to_add);
+            }
+        }
+        return builder.to_string();
+    }
+    case StateAndProperties::AriaErrorMessage: {
+        auto value = aria_data.aria_error_message_or_default();
+        return value.has_value() ? String::from_deprecated_string(value.value()) : String {};
+    }
+    case StateAndProperties::AriaExpanded:
+        return ARIA::optional_bool_to_string(aria_data.aria_expanded_or_default());
+    case StateAndProperties::AriaFlowTo:
+        return id_reference_list_to_string(aria_data.aria_flow_to_or_default());
+    case StateAndProperties::AriaGrabbed:
+        return ARIA::optional_bool_to_string(aria_data.aria_grabbed_or_default());
+    case StateAndProperties::AriaHasPopup: {
+        auto value = aria_data.aria_has_popup_or_default();
+        switch (value) {
+        case AriaHasPopup::False:
+            return "false"_short_string;
+        case AriaHasPopup::True:
+            return "true"_short_string;
+        case AriaHasPopup::Menu:
+            return "menu"_short_string;
+        case AriaHasPopup::Listbox:
+            return "listbox"_string;
+        case AriaHasPopup::Tree:
+            return "tree"_short_string;
+        case AriaHasPopup::Grid:
+            return "grid"_short_string;
+        case AriaHasPopup::Dialog:
+            return "dialog"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaHidden:
+        return ARIA::optional_bool_to_string(aria_data.aria_hidden_or_default());
+    case StateAndProperties::AriaInvalid: {
+        auto value = aria_data.aria_invalid_or_default();
+        switch (value) {
+        case AriaInvalid::Grammar:
+            return "grammar"_short_string;
+        case AriaInvalid::False:
+            return "false"_short_string;
+        case AriaInvalid::Spelling:
+            return "spelling"_string;
+        case AriaInvalid::True:
+            return "true"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaKeyShortcuts:
+        return String::from_deprecated_string(aria_data.aria_key_shortcuts_or_default());
+    case StateAndProperties::AriaLabel:
+        return String::from_deprecated_string(aria_data.aria_label_or_default());
+    case StateAndProperties::AriaLabelledBy:
+        return id_reference_list_to_string(aria_data.aria_labelled_by_or_default());
+    case StateAndProperties::AriaLevel:
+        return ARIA::optional_integer_to_string(aria_data.aria_level_or_default());
+    case StateAndProperties::AriaLive: {
+        AriaLive value;
+        if (default_value.has<AriaLive>())
+            value = aria_data.aria_live_or_default(default_value.get<AriaLive>());
+        else
+            value = aria_data.aria_live_or_default();
+
+        switch (value) {
+        case AriaLive::Assertive:
+            return "assertive"_string;
+        case AriaLive::Off:
+            return "off"_short_string;
+        case AriaLive::Polite:
+            return "polite"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaModal:
+        return aria_data.aria_modal_or_default() ? "true"_short_string : "false"_short_string;
+    case StateAndProperties::AriaMultiLine:
+        return aria_data.aria_multi_line_or_default() ? "true"_short_string : "false"_short_string;
+    case StateAndProperties::AriaMultiSelectable:
+        return aria_data.aria_multi_selectable_or_default() ? "true"_short_string : "false"_short_string;
+    case StateAndProperties::AriaOrientation: {
+        AriaOrientation value;
+        if (default_value.has<AriaOrientation>())
+            value = aria_data.aria_orientation_or_default(default_value.get<AriaOrientation>());
+        else
+            value = aria_data.aria_orientation_or_default();
+
+        switch (value) {
+        case AriaOrientation::Horizontal:
+            return "horizontal"_string;
+        case AriaOrientation::Undefined:
+            return "undefined"_string;
+        case AriaOrientation::Vertical:
+            return "vertical"_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaOwns:
+        return id_reference_list_to_string(aria_data.aria_owns_or_default());
+    case StateAndProperties::AriaPlaceholder:
+        return String::from_deprecated_string(aria_data.aria_placeholder_or_default());
+    case StateAndProperties::AriaPosInSet:
+        return ARIA::optional_integer_to_string(aria_data.aria_pos_in_set_or_default());
+    case StateAndProperties::AriaPressed:
+        return ARIA::tristate_to_string(aria_data.aria_pressed_or_default());
+    case StateAndProperties::AriaReadOnly:
+        return aria_data.aria_read_only_or_default() ? "true"_short_string : "false"_short_string;
+    case StateAndProperties::AriaRelevant: {
+        StringBuilder builder;
+        auto value = aria_data.aria_relevant_or_default();
+        for (auto const relevant : value) {
+            StringView to_add;
+            switch (relevant) {
+            case AriaRelevant::Additions:
+                to_add = "additions"sv;
+                break;
+            case AriaRelevant::AdditionsText:
+                to_add = "additions text"sv;
+                break;
+            case AriaRelevant::All:
+                to_add = "all"sv;
+                break;
+            case AriaRelevant::Removals:
+                to_add = "removals"sv;
+                break;
+            case AriaRelevant::Text:
+                to_add = "text"sv;
+                break;
+            }
+            if (builder.is_empty())
+                builder.append(to_add);
+            else {
+                builder.append(" "sv);
+                builder.append(to_add);
+            }
+        }
+        return builder.to_string();
+    }
+    case StateAndProperties::AriaRequired:
+        return String::from_utf8(aria_data.aria_required_or_default() ? "true"sv : "false"sv);
+    case StateAndProperties::AriaRoleDescription:
+        return String::from_deprecated_string(aria_data.aria_role_description_or_default());
+    case StateAndProperties::AriaRowCount:
+        return ARIA::optional_integer_to_string(aria_data.aria_row_count_or_default());
+    case StateAndProperties::AriaRowIndex:
+        return ARIA::optional_integer_to_string(aria_data.aria_row_index_or_default());
+    case StateAndProperties::AriaRowSpan:
+        return ARIA::optional_integer_to_string(aria_data.aria_row_span_or_default());
+    case StateAndProperties::AriaSelected:
+        return ARIA::optional_bool_to_string(aria_data.aria_selected_or_default());
+    case StateAndProperties::AriaSetSize:
+        return ARIA::optional_integer_to_string(aria_data.aria_set_size_or_default());
+    case StateAndProperties::AriaSort: {
+        auto value = aria_data.aria_sort_or_default();
+        switch (value) {
+        case AriaSort::Ascending:
+            return "ascending"_string;
+        case AriaSort::Descending:
+            return "descending"_string;
+        case AriaSort::None:
+            return "none"_short_string;
+        case AriaSort::Other:
+            return "other"_short_string;
+        }
+        VERIFY_NOT_REACHED();
+    }
+    case StateAndProperties::AriaValueMax:
+        if (default_value.has<f64>())
+            return ARIA::optional_number_to_string(aria_data.aria_value_max_or_default(default_value.get<f64>()));
+        else
+            return ARIA::optional_number_to_string(aria_data.aria_value_max_or_default());
+    case StateAndProperties::AriaValueMin:
+        if (default_value.has<f64>())
+            return ARIA::optional_number_to_string(aria_data.aria_value_min_or_default(default_value.get<f64>()));
+        else
+            return ARIA::optional_number_to_string(aria_data.aria_value_min_or_default());
+    case StateAndProperties::AriaValueNow:
+        return ARIA::optional_number_to_string(aria_data.aria_value_now_or_default());
+    case StateAndProperties::AriaValueText:
+        return String::from_deprecated_string(aria_data.aria_value_text_or_default());
+    }
+    VERIFY_NOT_REACHED();
+}
+
+ErrorOr<String> tristate_to_string(Tristate value)
+{
+    switch (value) {
+    case Tristate::False:
+        return "false"_short_string;
+    case Tristate::True:
+        return "true"_short_string;
+    case Tristate::Undefined:
+        return "undefined"_string;
+    case Tristate::Mixed:
+        return "mixed"_short_string;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+ErrorOr<String> optional_integer_to_string(Optional<i32> value)
+{
+    if (value.has_value())
+        return String::number(value.value());
+    return String {};
+}
+
+ErrorOr<String> optional_bool_to_string(Optional<bool> value)
+{
+    if (!value.has_value())
+        return "undefined"_string;
+    if (value.value())
+        return "true"_short_string;
+    return "false"_short_string;
+}
+
+ErrorOr<String> optional_number_to_string(Optional<f64> value)
+{
+    if (!value.has_value())
+        return "undefined"_string;
+    return String::number(value.value());
+}
+ErrorOr<String> id_reference_list_to_string(Vector<DeprecatedString> const& value)
+{
+    StringBuilder builder;
+    for (auto const& id : value) {
+        if (builder.is_empty()) {
+            builder.append(id);
+        } else {
+            builder.append(" "sv);
+            builder.append(id);
+        }
+    }
+    return builder.to_string();
+}
+
+StringView state_or_property_to_string(StateAndProperties value)
+{
+    switch (value) {
+    case StateAndProperties::AriaActiveDescendant:
+        return "aria-activedescendant"sv;
+    case StateAndProperties::AriaAtomic:
+        return "aria-atomic"sv;
+    case StateAndProperties::AriaAutoComplete:
+        return "aria-autocomplete"sv;
+    case StateAndProperties::AriaBusy:
+        return "aria-busy"sv;
+    case StateAndProperties::AriaChecked:
+        return "aria-checked"sv;
+    case StateAndProperties::AriaColCount:
+        return "aria-colcount"sv;
+    case StateAndProperties::AriaColIndex:
+        return "aria-colindex"sv;
+    case StateAndProperties::AriaColSpan:
+        return "aria-colspan"sv;
+    case StateAndProperties::AriaControls:
+        return "aria-controls"sv;
+    case StateAndProperties::AriaCurrent:
+        return "aria-current"sv;
+    case StateAndProperties::AriaDescribedBy:
+        return "aria-describedby"sv;
+    case StateAndProperties::AriaDetails:
+        return "aria-details"sv;
+    case StateAndProperties::AriaDisabled:
+        return "aria-disabled"sv;
+    case StateAndProperties::AriaDropEffect:
+        return "aria-dropeffect"sv;
+    case StateAndProperties::AriaErrorMessage:
+        return "aria-errormessage"sv;
+    case StateAndProperties::AriaExpanded:
+        return "aria-expanded"sv;
+    case StateAndProperties::AriaFlowTo:
+        return "aria-flowto"sv;
+    case StateAndProperties::AriaGrabbed:
+        return "aria-grabbed"sv;
+    case StateAndProperties::AriaHasPopup:
+        return "aria-haspopup"sv;
+    case StateAndProperties::AriaHidden:
+        return "aria-hidden"sv;
+    case StateAndProperties::AriaInvalid:
+        return "aria-invalid"sv;
+    case StateAndProperties::AriaKeyShortcuts:
+        return "aria-keyshortcuts"sv;
+    case StateAndProperties::AriaLabel:
+        return "aria-label"sv;
+    case StateAndProperties::AriaLabelledBy:
+        return "aria-labelledby"sv;
+    case StateAndProperties::AriaLevel:
+        return "aria-level"sv;
+    case StateAndProperties::AriaLive:
+        return "aria-live"sv;
+    case StateAndProperties::AriaModal:
+        return "aria-modal"sv;
+    case StateAndProperties::AriaMultiLine:
+        return "aria-multiline"sv;
+    case StateAndProperties::AriaMultiSelectable:
+        return "aria-multiselectable"sv;
+    case StateAndProperties::AriaOrientation:
+        return "aria-orientation"sv;
+    case StateAndProperties::AriaOwns:
+        return "aria-owns"sv;
+    case StateAndProperties::AriaPlaceholder:
+        return "aria-placeholder"sv;
+    case StateAndProperties::AriaPosInSet:
+        return "aria-posinset"sv;
+    case StateAndProperties::AriaPressed:
+        return "aria-pressed"sv;
+    case StateAndProperties::AriaReadOnly:
+        return "aria-readonly"sv;
+    case StateAndProperties::AriaRelevant:
+        return "aria-relevant"sv;
+    case StateAndProperties::AriaRequired:
+        return "aria-required"sv;
+    case StateAndProperties::AriaRoleDescription:
+        return "aria-roledescription"sv;
+    case StateAndProperties::AriaRowCount:
+        return "aria-rowcount"sv;
+    case StateAndProperties::AriaRowIndex:
+        return "aria-rowindex"sv;
+    case StateAndProperties::AriaRowSpan:
+        return "aria-rowspan"sv;
+    case StateAndProperties::AriaSelected:
+        return "aria-selected"sv;
+    case StateAndProperties::AriaSetSize:
+        return "aria-setsize"sv;
+    case StateAndProperties::AriaSort:
+        return "aria-sort"sv;
+    case StateAndProperties::AriaValueMax:
+        return "aria-valuemax"sv;
+    case StateAndProperties::AriaValueMin:
+        return "aria-valuemin"sv;
+    case StateAndProperties::AriaValueNow:
+        return "aria-valuenow"sv;
+    case StateAndProperties::AriaValueText:
+        return "aria-valuetext"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+}
diff --git a/Userland/Libraries/LibWeb/ARIA/StateAndProperties.h b/Userland/Libraries/LibWeb/ARIA/StateAndProperties.h
new file mode 100644
index 0000000000..f40417b3ac
--- /dev/null
+++ b/Userland/Libraries/LibWeb/ARIA/StateAndProperties.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2023, Jonah Shafran <jonahshafran@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/String.h>
+#include <LibWeb/ARIA/ARIAMixin.h>
+#include <LibWeb/ARIA/RoleType.h>
+
+namespace Web::ARIA {
+
+enum class StateAndProperties {
+    AriaActiveDescendant,
+    AriaAtomic,
+    AriaAutoComplete,
+    AriaBusy,
+    AriaChecked,
+    AriaColCount,
+    AriaColIndex,
+    AriaColSpan,
+    AriaControls,
+    AriaCurrent,
+    AriaDescribedBy,
+    AriaDetails,
+    AriaDisabled,
+    AriaDropEffect,
+    AriaErrorMessage,
+    AriaExpanded,
+    AriaFlowTo,
+    AriaGrabbed,
+    AriaHasPopup,
+    AriaHidden,
+    AriaInvalid,
+    AriaKeyShortcuts,
+    AriaLabel,
+    AriaLabelledBy,
+    AriaLevel,
+    AriaLive,
+    AriaModal,
+    AriaMultiLine,
+    AriaMultiSelectable,
+    AriaOrientation,
+    AriaOwns,
+    AriaPlaceholder,
+    AriaPosInSet,
+    AriaPressed,
+    AriaReadOnly,
+    AriaRelevant,
+    AriaRequired,
+    AriaRoleDescription,
+    AriaRowCount,
+    AriaRowIndex,
+    AriaRowSpan,
+    AriaSelected,
+    AriaSetSize,
+    AriaSort,
+    AriaValueMax,
+    AriaValueMin,
+    AriaValueNow,
+    AriaValueText
+};
+
+using DefaultValueType = Variant<Empty, f64, AriaOrientation, AriaLive, bool, AriaHasPopup>;
+ErrorOr<String> state_or_property_to_string_value(StateAndProperties, AriaData const&, DefaultValueType = {});
+ErrorOr<String> tristate_to_string(Tristate);
+ErrorOr<String> optional_integer_to_string(Optional<i32>);
+ErrorOr<String> optional_bool_to_string(Optional<bool>);
+ErrorOr<String> optional_number_to_string(Optional<f64>);
+ErrorOr<String> id_reference_list_to_string(Vector<DeprecatedString> const&);
+StringView state_or_property_to_string(StateAndProperties);
+
+}
diff --git a/Userland/Libraries/LibWeb/CMakeLists.txt b/Userland/Libraries/LibWeb/CMakeLists.txt
index 1424770239..47057abfb5 100644
--- a/Userland/Libraries/LibWeb/CMakeLists.txt
+++ b/Userland/Libraries/LibWeb/CMakeLists.txt
@@ -5,6 +5,7 @@ set(SOURCES
     ARIA/ARIAMixin.cpp
     ARIA/ARIAMixin.idl
     ARIA/Roles.cpp
+    ARIA/StateAndProperties.cpp
     Bindings/AudioConstructor.cpp
     Bindings/HostDefined.cpp
     Bindings/ImageConstructor.cpp