diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index f127cb199bb..dbb2975c0ee 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -116,6 +116,10 @@ class MiscTests(unittest.TestCase):
         # than MAX_PATH if long paths support is disabled:
         # see RtlAreLongPathsEnabled().
         min_len = 2000   # characters
+        # On VxWorks, PATH_MAX is defined as 1024 bytes. Creating a path
+        # longer than PATH_MAX will fail.
+        if sys.platform == 'vxworks':
+            min_len = 1000
         dirlen = 200     # characters
         dirname = 'python_test_dir_'
         dirname = dirname + ('a' * (dirlen - len(dirname)))
diff --git a/Misc/NEWS.d/next/Tests/2020-05-20-17-28-46.bpo-31904.yt83Ge.rst b/Misc/NEWS.d/next/Tests/2020-05-20-17-28-46.bpo-31904.yt83Ge.rst
new file mode 100644
index 00000000000..1679801a111
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2020-05-20-17-28-46.bpo-31904.yt83Ge.rst
@@ -0,0 +1 @@
+Fix os module failures for VxWorks RTOS.