diff --git a/Libraries/LibWeb/HighResolutionTime/Performance.idl b/Libraries/LibWeb/HighResolutionTime/Performance.idl
index 0ee1307bde7..c5e32f3e466 100644
--- a/Libraries/LibWeb/HighResolutionTime/Performance.idl
+++ b/Libraries/LibWeb/HighResolutionTime/Performance.idl
@@ -1,5 +1,6 @@
 #import <DOM/EventTarget.idl>
 #import <HighResolutionTime/DOMHighResTimeStamp.idl>
+#import <NavigationTiming/PerformanceExtensions.idl>
 #import <NavigationTiming/PerformanceNavigation.idl>
 #import <NavigationTiming/PerformanceTiming.idl>
 #import <PerformanceTimeline/PerformanceEntry.idl>
@@ -34,11 +35,4 @@ interface Performance : EventTarget {
     PerformanceEntryList getEntries();
     PerformanceEntryList getEntriesByType(DOMString type);
     PerformanceEntryList getEntriesByName(DOMString name, optional DOMString type);
-
-    // https://w3c.github.io/navigation-timing/#extensions-to-the-performance-interface
-    // Obsolete "Navigation Timing" extensions to the Performance interface
-    [SameObject]
-    readonly attribute PerformanceTiming timing;
-    [SameObject]
-    readonly attribute PerformanceNavigation navigation;
 };
diff --git a/Libraries/LibWeb/NavigationTiming/PerformanceExtensions.idl b/Libraries/LibWeb/NavigationTiming/PerformanceExtensions.idl
new file mode 100644
index 00000000000..f62b7a002c9
--- /dev/null
+++ b/Libraries/LibWeb/NavigationTiming/PerformanceExtensions.idl
@@ -0,0 +1,8 @@
+// https://w3c.github.io/navigation-timing/#extensions-to-the-performance-interface
+[Exposed=Window]
+partial interface Performance {
+    [SameObject]
+    readonly attribute PerformanceTiming timing;
+    [SameObject]
+    readonly attribute PerformanceNavigation navigation;
+};
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
index de3de012731..f8bd60ee875 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
@@ -3136,6 +3136,19 @@ static void collect_attribute_values_of_an_inheritance_stack(SourceGenerator& fu
 
         // FIXME: Check if the attributes are exposed.
 
+        // NOTE: Add more specified exposed global interface groups when needed.
+        StringBuilder window_exposed_only_members_builder;
+        SourceGenerator window_exposed_only_members_generator { window_exposed_only_members_builder, function_generator.clone_mapping() };
+        auto generator_for_member = [&](auto const& name, auto& extended_attributes) -> SourceGenerator {
+            if (auto maybe_exposed = extended_attributes.get("Exposed"); maybe_exposed.has_value()) {
+                auto exposed_to = MUST(IDL::parse_exposure_set(name, *maybe_exposed));
+                if (exposed_to == IDL::ExposedTo::Window) {
+                    return window_exposed_only_members_generator.fork();
+                }
+            }
+            return function_generator.fork();
+        };
+
         // 1. Let id be the identifier of attr.
         // 2. Let value be the result of running the getter steps of attr with object as this.
 
@@ -3154,7 +3167,7 @@ static void collect_attribute_values_of_an_inheritance_stack(SourceGenerator& fu
             if (!attribute.type->is_json(interface_in_chain))
                 continue;
 
-            auto attribute_generator = function_generator.fork();
+            auto attribute_generator = generator_for_member(attribute.name, attribute.extended_attributes);
             auto return_value_name = ByteString::formatted("{}_retval", attribute.name.to_snakecase());
 
             attribute_generator.set("attribute.name", attribute.name);
@@ -3211,6 +3224,16 @@ static void collect_attribute_values_of_an_inheritance_stack(SourceGenerator& fu
 
             constant_generator.append(R"~~~(
     MUST(result->create_data_property("@constant.name@"_fly_string, constant_@constant.name@_value));
+)~~~");
+        }
+
+        if (!window_exposed_only_members_generator.as_string_view().is_empty()) {
+            auto window_only_property_declarations = function_generator.fork();
+            window_only_property_declarations.set("defines", window_exposed_only_members_generator.as_string_view());
+            window_only_property_declarations.append(R"~~~(
+    if (is<HTML::Window>(realm.global_object())) {
+@defines@
+    }
 )~~~");
         }
     }
diff --git a/Tests/LibWeb/Text/expected/performance-timing-and-navigation-not-exposed-outside-of-window.txt b/Tests/LibWeb/Text/expected/performance-timing-and-navigation-not-exposed-outside-of-window.txt
new file mode 100644
index 00000000000..066b54a3802
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/performance-timing-and-navigation-not-exposed-outside-of-window.txt
@@ -0,0 +1,6 @@
+(window) navigation: object
+(window) timing: object
+(window) performance JSON: {"timeOrigin":[removed-potentially-flaky-time-value],"timing":{"navigationStart":[removed-potentially-flaky-time-value],"unloadEventStart":[removed-potentially-flaky-time-value],"unloadEventEnd":[removed-potentially-flaky-time-value],"redirectStart":[removed-potentially-flaky-time-value],"redirectEnd":[removed-potentially-flaky-time-value],"fetchStart":[removed-potentially-flaky-time-value],"domainLookupStart":[removed-potentially-flaky-time-value],"domainLookupEnd":[removed-potentially-flaky-time-value],"connectStart":[removed-potentially-flaky-time-value],"connectEnd":[removed-potentially-flaky-time-value],"secureConnectionStart":[removed-potentially-flaky-time-value],"requestStart":[removed-potentially-flaky-time-value],"responseStart":[removed-potentially-flaky-time-value],"responseEnd":[removed-potentially-flaky-time-value],"domLoading":[removed-potentially-flaky-time-value],"domInteractive":[removed-potentially-flaky-time-value],"domContentLoadedEventStart":[removed-potentially-flaky-time-value],"domContentLoadedEventEnd":[removed-potentially-flaky-time-value],"domComplete":[removed-potentially-flaky-time-value],"loadEventStart":[removed-potentially-flaky-time-value],"loadEventEnd":[removed-potentially-flaky-time-value]},"navigation":{"type":[removed-potentially-flaky-time-value],"redirectCount":[removed-potentially-flaky-time-value],"TYPE_NAVIGATE":0,"TYPE_RELOAD":1,"TYPE_BACK_FORWARD":2,"TYPE_RESERVED":255}}
+(worker) navigation: undefined
+(worker) timing: undefined
+(worker) performance JSON: {"timeOrigin":[removed-potentially-flaky-time-value]}
diff --git a/Tests/LibWeb/Text/input/performance-timing-and-navigation-not-exposed-outside-of-window.html b/Tests/LibWeb/Text/input/performance-timing-and-navigation-not-exposed-outside-of-window.html
new file mode 100644
index 00000000000..57d65f4151c
--- /dev/null
+++ b/Tests/LibWeb/Text/input/performance-timing-and-navigation-not-exposed-outside-of-window.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<script type="worker">
+    globalThis.onmessage = () => {
+        const result = [];
+        result.push("(worker) navigation: " + typeof performance.navigation);
+        result.push("(worker) timing: " + typeof performance.timing);
+        result.push("(worker) performance JSON: " + JSON.stringify(performance));
+        postMessage(result);
+    }
+</script>
+<script src="include.js"></script>
+<script>
+    asyncTest((done) => {
+        const replacePotentiallyFlakyTimes = (string) => {
+            return string.replace(/("[a-zA-Z]+":)(\d+(\.\d+)?)/g, "$1[removed-potentially-flaky-time-value]");
+        };
+
+        println("(window) navigation: " + typeof performance.navigation);
+        println("(window) timing: " + typeof performance.timing);
+        println("(window) performance JSON: " + replacePotentiallyFlakyTimes(JSON.stringify(performance)));
+
+        const workerSource = document.querySelector('[type=worker]').innerText;
+        const workerBlob = new Blob([workerSource], { type: "text/javascript" });
+        const workerBlobURL = URL.createObjectURL(workerBlob);
+        const worker = new Worker(workerBlobURL);
+        worker.onmessage = ({ data }) => {
+            for (const string of data) {
+                println(replacePotentiallyFlakyTimes(string));
+            }
+
+            done();
+        };
+
+        worker.postMessage("start");
+    });
+</script>