diff --git a/Userland/Libraries/LibWeb/Streams/AbstractOperations.cpp b/Userland/Libraries/LibWeb/Streams/AbstractOperations.cpp
index 2e39925f61..af3d9a72bd 100644
--- a/Userland/Libraries/LibWeb/Streams/AbstractOperations.cpp
+++ b/Userland/Libraries/LibWeb/Streams/AbstractOperations.cpp
@@ -1178,6 +1178,20 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<WritableStream>> create_writable_stream(JS:
     return stream;
 }
 
+// https://streams.spec.whatwg.org/#initialize-readable-stream
+void initialize_readable_stream(ReadableStream& stream)
+{
+    // 1. Set stream.[[state]] to "readable".
+    stream.set_state(ReadableStream::State::Readable);
+
+    // 2. Set stream.[[reader]] and stream.[[storedError]] to undefined.
+    stream.set_reader({});
+    stream.set_stored_error({});
+
+    // 3. Set stream.[[disturbed]] to false.
+    stream.set_disturbed(false);
+}
+
 // https://streams.spec.whatwg.org/#initialize-writable-stream
 void initialize_writable_stream(WritableStream& stream)
 {
diff --git a/Userland/Libraries/LibWeb/Streams/AbstractOperations.h b/Userland/Libraries/LibWeb/Streams/AbstractOperations.h
index 27b8d74423..f45f5c55cf 100644
--- a/Userland/Libraries/LibWeb/Streams/AbstractOperations.h
+++ b/Userland/Libraries/LibWeb/Streams/AbstractOperations.h
@@ -91,6 +91,7 @@ void readable_byte_stream_controller_invalidate_byob_request(ReadableByteStreamC
 bool readable_byte_stream_controller_should_call_pull(ReadableByteStreamController const&);
 
 WebIDL::ExceptionOr<JS::NonnullGCPtr<WritableStream>> create_writable_stream(JS::Realm& realm, StartAlgorithm&& start_algorithm, WriteAlgorithm&& write_algorithm, CloseAlgorithm&& close_algorithm, AbortAlgorithm&& abort_algorithm, double high_water_mark, SizeAlgorithm&& size_algorithm);
+void initialize_readable_stream(ReadableStream&);
 void initialize_writable_stream(WritableStream&);
 
 WebIDL::ExceptionOr<JS::NonnullGCPtr<WritableStreamDefaultWriter>> acquire_writable_stream_default_writer(WritableStream&);