diff --git a/sdks/python/test-suites/portable/py2/build.gradle b/sdks/python/test-suites/portable/py2/build.gradle
index 5ceac52d35ba..20a3de4033b9 100644
--- a/sdks/python/test-suites/portable/py2/build.gradle
+++ b/sdks/python/test-suites/portable/py2/build.gradle
@@ -128,6 +128,8 @@ task crossLanguagePortableWordCount {
         "--shutdown_sources_on_final_watermark",
         "--environment_cache_millis=10000",
         "--expansion_service_jar=${testServiceExpansionJar}",
+        // Writes to local filesystem might fail for multiple SDK workers.
+        "--sdk_worker_parallelism=1"
     ]
     exec {
       executable 'sh'