diff --git a/pw_transfer/py/pw_transfer/client.py b/pw_transfer/py/pw_transfer/client.py
index 27c5459598..30d7d86a85 100644
--- a/pw_transfer/py/pw_transfer/client.py
+++ b/pw_transfer/py/pw_transfer/client.py
@@ -74,6 +74,9 @@ def __init__(self,
         self._write_stream: Optional[BidirectionalStreamingCall] = None
 
         self._loop = asyncio.new_event_loop()
+        # If constructed from non-main thread, set the event loop.
+        if threading.current_thread() is not threading.main_thread():
+            asyncio.set_event_loop(self._loop)
 
         # Queues are used for communication between the Manager context and the
         # dedicated asyncio transfer thread.