diff --git a/s3torchconnector/tst/e2e/test_mountpoint_client_parallel_access.py b/s3torchconnector/tst/e2e/test_mountpoint_client_parallel_access.py
new file mode 100644
index 00000000..ba834cbb
--- /dev/null
+++ b/s3torchconnector/tst/e2e/test_mountpoint_client_parallel_access.py
@@ -0,0 +1,66 @@
+import os
+import random
+import time
+import threading
+import pytest
+from s3torchconnector._s3client import S3Client
+from s3torchconnectorclient._mountpoint_s3_client import MountpointS3Client
+
+class S3ClientWithoutLock(S3Client):
+    @property
+    def _client(self) -> MountpointS3Client:
+        if self._client_pid is None or self._client_pid != os.getpid():
+            self._client_pid = os.getpid()
+            # `MountpointS3Client` does not survive forking, so re-create it if the PID has changed.
+            self._real_client = self._client_builder()
+        time.sleep(10)
+        assert self._real_client is not None
+        return self._real_client
+
+    def invalidate_client(self):
+        self._real_client = None
+
+def access_client(client, error_event):
+    try:
+        if not error_event.is_set():
+            client._client
+            print(f"Successfully accessed by thread {threading.current_thread().name}")
+    except AssertionError as e:
+        print(f"AssertionError in thread {threading.current_thread().name}: {e}")
+        error_event.set()
+
+def invalidate_client(client, error_event):
+    if not error_event.is_set():
+        client.invalidate_client()
+        print(f"Client invalidated by thread {threading.current_thread().name}")
+
+def test_multiple_thread_accessing_mountpoint_client_in_parallel():
+    print("Running test without lock...")
+    client = S3ClientWithoutLock("us-west-2")
+    error_event = threading.Event()
+
+    # Start one accessor thread
+    accessor_thread = threading.Thread(target=access_client, args=(client, error_event,), name="Accessor")
+    accessor_thread.start()
+
+    # Create and start multiple invalidator threads
+    invalidator_threads = []
+    num_invalidators = 500  # Number of invalidator threads
+
+    for i in range(num_invalidators):
+        if error_event.is_set():
+            break
+        invalidator_thread = threading.Thread(target=invalidate_client, args=(client, error_event,),
+                                              name=f"Invalidator-{i + 1}")
+
+        invalidator_threads.append(invalidator_thread)
+        time.sleep(random.uniform(0.1, 0.5))
+        invalidator_thread.start()
+
+    accessor_thread.join()
+
+    for thread in invalidator_threads:
+        thread.join(timeout=1)
+
+    if error_event.is_set():
+        pytest.fail("Test failed due to AssertionError in one of the threads.")
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