diff --git a/pw_unit_test/py/pw_unit_test/rpc.py b/pw_unit_test/py/pw_unit_test/rpc.py
index 5ec0cfd..5644d15 100644
--- a/pw_unit_test/py/pw_unit_test/rpc.py
+++ b/pw_unit_test/py/pw_unit_test/rpc.py
@@ -126,7 +126,7 @@
     test_responses = iter(
         unit_test_service.Run(
             report_passed_expectations=report_passed_expectations,
-            timeout_s=timeout_s))
+            pw_rpc_timeout_s=timeout_s))
 
     # Read the first response, which must be a test_case_start message.
     first_response = next(test_responses)